Examples of one creator through one or multiple series:
Amy Acker has never been considered a bad actress. Her roles on Angel and Dollhouse were praised. Her acting in Person of Interest as the sociopathic serial killer hacker Root was likewise met with universal acclaim, especially since she initially appeared as a subdued, innocent therapist before switching to herGiggling Villain natural state. However, in the Season 3 episode "Aletheia", she hit it out of the park when Root spoke for the Machine directly. She managed a perfect not-quite Creepy Monotone, balancing ambiguously between "creepy computer is spying on us" and "benevolent AI doesn't know how to talk to people." Earlier in the last few episodes of Angel, she really impressed by playing both Fred and Illyria in one episode — and even switching back and forth within the same scene.
Chris Addison's acting roles consisted entirely of comedy (most notably The Thick of It) until his role in Skins as the headmaster of the college that the series is set in, later revealed to be the father of a main character. This role started off as another comedic one, his character being a strict teacher and very resentful of his daughter's boyfriend, but it took a dramatic turn when the character of his daughter was killed off and the emotional scene where he breaks the news to her boyfriend left viewers surprised that not only was he suddenly doing serious acting but was also very good at it!
Ashley Boetcherr in Gortimer Gibbons Life On Normal Street, especially the climactic scene in the second season finale in "Mel vs. the Future" where she has to come to terms with her mother's death. Great acting for a relatively innocent Slice of Life show.
Peter Boyle appeared in a few dramatic films throughout his career, but was best known for small character roles and comic parts, especially as the titular monster in Young Frankenstein. In the 90's, he played Grumpy Bear Frank Barone on Everybody Loves Raymond, seemingly cementing his legacy in comedy. It was a surprise, then, when he appeared on The X-Files in the episode "Clyde Bruckman's Final Repose"—especially because show creator Chris Carter had a strong "no famous guest stars" policy; Boyle's skill was enough to have him make an exception. In the episode, Boyle plays the titular character, a depressed, neurotic Seer who has the "gift" of foretelling how people will die. As Bruckman, Boyle is equal parts darkly comic, philosophical, morose, sarcastic, and resigned, a major departure from the cranky bluster of Frank Barone. "Clyde Bruckman's Final Repose" is frequently cited as one of the best—if not the best—episodes of The X-Files (some critics go even further and say it's one of the best episodes of television period), with Boyle's performance (which won him an Emmy for Best Guest Star) cited as a major reason for why it works so well.
Toni Colette on United States of Tara. Not only portraying five people living in the same body of varying ages and genders but playing the main personality badly impersonating one of the other personalities. Wow.
Misha Collins' Castiel became one of the breakout characters of Supernatural for a reason. While an Angel who's constantly stoic and at times Literal-Minded doesn't sound like something to write home about, the episode "The Rapture" is widely praised as one of the best examples of Misha's acting ability. In this episode, he transitioned from the relatively emotionless Castiel to his very human vessel Jimmy, and brought many viewers to tears in the process. Notable since this episode is during his first season on the show, before which he was largely unknown. Then came the episodes "The French Mistake", where Misha seamlessly transitions from Castiel to his tweet-happy self, "The Man Who Would Be King", where Castiel is begging for a sign from God, and "The Man Who Knew Too Much", where we learn that Misha can be really scary when needed, which are all evidence of this.
Bradley Cooper has been known as primarily as a comedic actor, but long before he was ever famous, Cooper more than held his own on Alias. Will's early quest to uncover the truth about Danny's murder was acclaimed at the time, whereas episodes like "Almost Thirty Years" (especially the torture scenes) and "There's Only One Sydney Bristow" really emphasized how good of an actor Cooper is.
Brett Dalton was a novice actor when he started playing the rather boring character of Grant Ward in Agents of S.H.I.E.L.D.. There were a few hints of his acting ability like in the episode where he was afflicted by a rage artifact, but for the most part, he didn't have a chance to shine. When Ward was revealed to be a mole, it still didn't quite help, since Dalton was Acting in the Dark, but after the reveal, he proved to be able to switch between "bland big-brother soldier" to "Smug Snake spy who loves his job" at the drop of a hat. Then in the third season, Dalton started playing Hive, an ancient Inhuman of god-level power. He completely hit it out of the park, portraying a completely calm and collected devil-figure with subtle and dangerous emotions under the surface.
William B. Davis: In The X-Files, Gillian Anderson became pregnant and had to be written out for a while. Desperate for something to create a focal point in her absence, the producer chose Davis, then a minor extra who had previously been through the series in a role so small that his character wasn't given a name and was credited simply as... the Cigarette Smoking Man. Turns out, he was a very good actor, and did so well he became the primary antagonist for the entire series.
Firass Dirani had generally been considered a competent and likable young actor, but nothing truly special. The Underbelly: The Golden Mile happened, in which he showcases his dramatic chops to fullest. The show earned him rave reviews and he eventually ended up winning a Logie Award.
When Nina Dobrev was cast in the roles of Elena and Katherine for The Vampire Diaries most people thought she would never be able to carry the series, let alone play two completely different characters, judging by her performances on Degrassi. Fast forward to mid-Season 1, and people started to realize just how talented she actually is. Fast forward to Season 2, and she had viewers and critics floored by how easily she slips between Elena and Katherine while keeping both of them completely in character. If there were any critics left, They've almost certainly been silenced by Dobrev's performance in Season 4 when she shows uncanny skill in portraying Elena's slow descent into vampirism and her desperate struggle to hold onto her humanity and in Season 5 when she does terrific work as Elena, gives a heartbreaking performance as Katherine realizes that she is dying and cannot save herself, summoning sympathy for an otherwise deeply unlikeable character and her episodes as Amara, when she is both functional and after she has undergone a complete mental breakdown from years of torture. Even fans who don't like Elena have commented on how impressive her acting is.
George Eads of CSI was a passable but unremarkable actor, but then came the Season 5 episodes "Grave Danger: Volume 1" and "Grave Danger: Volume 2." Wow. Especially considering that he spends about 90% of "Grave Danger" in a box the size of a coffin.
Even some huge WWE fans didn't expect wrestler Edge to make it as an actor, especially those who saw his film Bending the Rules. Then he joined the cast of Haven...
Martin Freeman. Sherlock. "The Reichenbach Fall". He deserved that BAFTA for series 1 and there's no doubt about it, and we've always known he could act, but "Reichenbach" is a whole different ballgame. Whatever remaining critics of his are out there, they've been silenced. And how.
Aiden Gallagher, a 15-year-old actor best known for playing Nicky in the Nickelodeon sitcom Nicky, Ricky, Dicky and Dawn, surprised and impressed audiences with his excellent performance as Number Five in The Umbrella Academy, giving the role weight, melancholy, and quiet rage not usually seen in a performer so young. Through his nuanced facial expressions and deft use of body language, he's somehow totally believable as a 53-year-old trapped in a 13-year-old's body. He also managed to successfully convince the audience that he was in love with a mannequin, and treat his older cast mates like annoying children.
Ricky Gervais has built a career playing Deadpan Snarkers or comedic buffoons (or both) through his various shows. He unveiled a surprising softer side on Derek, and then stunned everyone by revealing that he can pull off drama just as well as comedy on After Life (2019), playing a grieving widower who oscillates between the usual Gervais snark and genuinely affecting pathos.
While no one denies that Donald Glover is a talented Jack-of-All-Trades, most of his acting roles tend to be likeable nerds with varying levels of immaturity - except his creepy turn as Teddy Perkins in the fan favorite episode of Atlanta playing a seemingly fragile old millionaire with vitiligo, complex father issues and a sinister motive which surprised even his most die hard fans.
Inverted with Jon Hamm. He received tons of praise for his remarkably tense, understated performance on Mad Men and is praised as the reason the show is so successful. Many viewers have been surprised by his work in stuff like 30 Rock and Bridesmaids, which qualify more as "He Really Can Be Funny".
Not that his acting skills were in doubt before, but many critics have deemed Mark Harmon's terrifying performances as Serial Killer Ted Bundy and murderer Thomas Capano (in two separate miniseries) as among his best work. Probably because they were such a departure from both his Nice Guy persona and his typical doctor/cop roles.
Neil Patrick Harris is an odd example. He's re-invented himself as a comedic actor in the last decade after being known as a child star in The '80s. Then came Dr. Horrible's Sing-Along Blog. He already had plenty of fans because he's just a cool guy, but compared to his role in the Harold and Kumar films, his role as Dr. Horrible was surprisingly good. He was also very touching as a disturbed, socially-awkward murderer in Law & Order: Criminal Intent. He also had some serious Broadway cred in between his stints on television.
Josh Hartnett: After his series Penny Dreadful debuted, he was pegged by many critics as the weak link of the cast. Come "Possession", specifically the scene where Vanessa's demon appears in Ethan's form and his "good ol' boy" cowboy charm suddenly goes from sexy to Nightmare Fuel in a matter of seconds, and the scene where Ethan exorcises Vanessa, Hartnett really takes a level in acting badassery.
Anyone looking at the early career of Teri Hatcher would be hard pressed to describe her as anything other than Ms. Fanservice, but move forward 20 years and she has earned a Golden Globe and an Emmy nomination for Desperate Housewives.
Who knew that Sean Hayes, the guy that played a bimbo Camp Gay for years in Will & Grace, could act out a breakdown in Scrubs so easily?
Avan Jogia, known to some as Beck from the Nickelodeon show Victorious, later starred as the main character on ABC Family's drama/mystery Twisted. His performance in Twisted really shows how well he can actually act when given a larger role and a more serious atmosphere.
Orlando Jones, widely remembered as "The 7-Up Guy" and occasionally remembered as detective Magnus Olsdatter from Pushing Daisies, was cast as Anansi for American Gods. Some fans of the book were apprehensive, unsure that he could carry the role on his comedic chops alone, but it turned out his abilities went beyond that.
Downplayed with Dafne Keen. While no one who saw Logan would leave the theater disputing whether she can act, when talk of a spinoff X-23 movie began many questioned whether she could support a lead role, (especially considering she had so little dialogue in Logan that wasn't just screaming and snarling) and wanted to see her replaced by an older actress. Her leading role as Lyra on His Dark Materials silenced that debate after the first episode.
Shane Kippel in Degrassi. He was criticized a lot during his tenure on the show (primarily earlier seasons) for not really being able to act when it came to dramatic sequences (which, being Degrassi, did happen sometimes). Then he played a supporting character in the film Dog Pound, which caused everybody to go back and do a Double Take... even IMDB gave him praise for his performance in it.
Hugh Laurie's star turn in House would have been surprising to American audiences had they already been familiar with his work in British comedy. Not that anyone ever doubted his comedic chops. The initial British reaction to hearing about the House series was to either avoid it, believing Hugh Laurie in drama would be a disaster, or to watch it solely to see if he could pull it off. The buzz the show generated in Britain was huge when consensus agreed that Hugh Laurie was good at drama. (Not that kept it from being dropped by its initial UK broadcaster.
In the iconic series Xena: Warrior Princess, Hudson Leick, a young actress who had previously played bit roles in soaps, played Callisto, one of the most complex and heart-rending villains to grace the stage of TV. The range and depth of her acting, the way she developed the character, and the transition to Callisto's ultimate redemption were all absolutely brilliant. She also played the title character Xena very well for a few episodes, and other small parts were played with the same ingenuity. That her undeniable talent wasn't picked up for much larger roles after Xena is a true example of Hollywood overlooking a wonderful actor who deserved much more.
Remember Judith Light from Who's the Boss?? Well, before she was Tony Danza's co-star, she was on One Life to Live. As Karen Wolek, who had to admit to being a prostitute on the witness stand at her friend's murder trial. The scene is here. She won the 1980 Daytime Emmy for Best Actress for that scene, BTW.
Many people thought Robin Lord-Taylor would be doomed to be forever known as that scrawny kid from Accepted. Then they watched him in Gotham give one of the most terrifying performances of Oswald Cobblepot ever and, well, putting it lightly, they were convinced otherwise. He's become one of the highest-praised aspects of the show.
Disney Channel star Demi Lovato won critical praise for their guest role on a 2010 Grey's Anatomy episode, as a suicidal patient.
Howie Mandel was a regular performer for all six seasons of the Emmy-winning medical drama St. Elsewhere. Playing a doctor. And his character had his fair share of serious scenes. Mandel is a comedian, who is notorious for over-the-top zany comedy, displayed in his comedy specials, films such as Walk Like a Man, where he plays a man literally raised by wolves, Bobby's World, where he voices a cartoon toddler, and various other things and YMMV if he's funny or excruciating. He's also taken to hosting in recent years, having hosted Deal or No Deal and been a judge on America's Got Talent. Seeing him on this series, in a role that isn't entirely comedic (at least not really any more so than Ed Begley, Jr., Eric Laneuville or even William Daniels), is very jarring. But he doesn't stick out like a sore thumb at all, and if this series was all you knew him from, you'd think he was a dramatic actor.
Tatiana Maslany was just a minor actress with a few roles under her belt... and then came Orphan Black. In the first season alone, she plays nine different clones, all with different mannerisms, accents, speech patterns, and personalities. From the wild and rough British Sarah to the competent but unraveling Beth to the tightly-wound Allison to the genius and excitable Cosima to the religious fanatic Helena, she plays every single one of them absolutely perfectly, even when they are onscreen at the same time. Even better, multiple times the clones have to play each other, and it's still quite easy to tell which character Maslany is playing as the other character. Sarah spends most of the first season playing Beth competently enough, but when Allison has to play Sarah she's clearly trying too hard to be cool and aloof. Helena pretends to be Sarah pretending to be Beth and knows she can't fake the accent, so she keeps her sentences short and curt; even so, all the cops can tell that there is something off about her body language since Helena moves like a predator. Sarah has to play Allison when Allison gets drunk at a party, and while Sarah does an excellent job, she can't quite keep up with the energy that Allison is supposed to have. One of the long-running jokes of the fandom was that Maslany wasn't going to get the award she deserved until she was playing literally the entire cast. She finally got nominated for her work on season 3 and won an Emmy for season 4.
While few who saw him on The O.C. was in doubt that he could act, Ben McKenzie has spent much of his post teen-idol career showing his considerable talent in roles such as Junebug where he plays an ignorant character seething with resentment that his brother has been so successful and all too aware that he is viewed as the family screw-up, Batman: Year One where he played the title character and proved equally capable of making a convincing shallow playboy and tortured man unable to move on and in a one-man version of Johnny Got His Gun where he earned rave reviews for a role previously played by the heavyweight likes of James Cagney and Jeff Daniels. He has continued to earn praise for his part on Southland which has solidified his ascent as a serious actor.
Many people went into The Orville thinking it was going to be a purely comedic Star Trek parody, and Seth MacFarlane would simply play one of his animated characters in real life. While the series has comedic moments it is also thoughtful and dramatic, and MacFarlane has demonstrated real dramatic acting chops, especially for a man known for voice acting and singing, in using only his face to wordlessly convey real emotional depth.
Mos Def: Another one complementing his entry on this trope's film examples page, he's in the TV biopic Something the Lord Made where he played pioneering black cardiac surgeon Vivien Thomas. He managed to not only hold his ground but possibly surpassed it against Alan Rickman. Mos Def was nominated for a Golden Globe and an Emmy. Mos has also received praise for his performance in the sixth season of Dexter.
Dylan O'Brien was considered one of the stronger actors in Teen Wolf from the start, his role as Stiles was mostly restricted to Plucky Comic Relief and Deadpan Snarker, raising questions of how well he could play roles outside that range. Then in Season 3b, he took on void!Stiles, playing a thousand-year-old evil nogitsune spirit controlling his body. He pulled the role off flawlessly and his performance was lauded as one of the best Teen Wolf villains in the whole show and proved him as the truly exceptional, stand out actor of the cast. In one episode, in particular, O'Brien expertly played normal Stiles, the nogitsune, the nogistune pretending to be Stiles and a broken, traumatized Stiles at the end.
Mike O'Malley is known for subpar comedies that somehow made it past five seasons (*cough* Yes, Dear *cough*), Nickelodeon game shows, and being a Boston sports fan. However, it wasn't until his turn on Glee as Kurt's father that people realized that he can actually act! He's also playing a recurring role on Parenthood. That said, his history with this trope goes back earlier than Glee and Parenthood. Case in point: the NBC series My Own Worst Enemy where he switches back and forth between a falsely created personality as a loving husband and his true self as a badass killing machine spy.
And don't forget his turn in The Sopranos as a compulsive gambler in way over his head. When he finally breaks down in anguish, it is absolutely heartbreaking.
Ellen Pompeo, after playing Meredith Grey in Grey's Anatomy as a perpetually vague, droll, half-asleep character for what seemed hundreds of episodes, all of a sudden confronts her lucid mother about how she just can't deal with yet another upheaval in her life. It's not one of Izzie Stevens's hysterical meltdowns; it's quiet, understated, and completely rips your heart out.
Iwan Rheon in Misfits was certainly never considered a bad actor, and was arguably the best of the main cast. However his role as Future!Simon shows his clear talent: through subtly changing his behavior, Rheon in a few scenes clearly showed the character development Simon has undergone and exhibits simultaneously a vastly different personality, yet with a few glimpses of the Simon we know and love peeking through. Not an easy job to handle. And then he followed it up with his role in Game of Thrones (see below)...
Emmy Rossum was mainly known for giving bland, wide-eyed, ingenue performances. Then came the U.S. remake of Shameless, where she not only proved she could act her ass off, but somehow managed to come off as a better actor than William H. Macy.
Her debut on Star Trek: Voyager was met with a degree of eye-rolling from the fanbase: "Oh great, here comes a shameless attempt at Ms. Fanservice, Narm ahoy, etc..." Then came that episode where she had to manifest a dozen different personalities in 20 minutes... Hidden Depths indeed.
"Body and Soul" was also a very good episode for Jeri Ryan, as she had act as the Doctor...which she does flawlessly, right down to all of Robert Picardo's little tics and mannerisms.
She also did well as a temporary substitute for Gina Bellman in Leverage, to the point that she occasionally returned for several episodes even after Gina returned to the show.
Andy Samberg, probably best known for his The Lonely Island songs such as "Dick in a Box", wins a Golden Globe for his work on the sitcom Brooklyn Nine-Nine and proves he can pull serious scenes.
Willard Scott, besides being a weatherman on the Today show, has done a few sporadic acting roles, all very lightweight (many of them were Washington, D.C. children's shows during the 1950s and 1960s, i.e. Bozo the Clown) and in general is particularly well-known for being an adorkableNice Guy, but some of those roles have been surprising:
"The Conscience Of The King" is a particularly good episode for this. It's most evident when Kirk is listening to the background on Kodos from the computer and later when he gives "Karidian" the speech to read; in both cases, he's virtually still, but Shatner conveys perfectly the lingering trauma that Kirk retains from the massacre.
Jimmi Simpson is a character actor whose career has been split pretty evenly between comedic roles and serious roles. He is most recognized, however, as one of the twincestuous McPoyle brothers from It's Always Sunny in Philadelphia. Fans of that show who see him in something more serious (House of Cards, for example) are likely to think, "I had no idea that Liam McPoyle could act!"
Tori Spelling has been Hollywood's favorite punching bag for years, usually seen as a product of nepotism and a talentless little rich girl. In an effort to defy this, she put together a little Life Embellished sitcom in 2006 called So NoTORIous. The critics who normally got their kicks trashing her, almost unanimously (and frequently, begrudgingly) praised the show, saying it was better than they assumed, and that Spelling is actually funny and pretty good at comedy, enjoying that, rather than a vanity project, she was willing to make fun of herself as much as anyone else.
David Tennant is known as a very good actor, but also as one hell of a Large Ham owing to his time on Doctor Who and the film adaptation of Harry Potter and the Goblet of Fire. So people who saw The Escape Artist (the 2013 BBC drama series) were blown away by his depiction of a court barrister whose life starts taking a turn for the worse, culminating in him showing himself as a magnificent bastard by murdering his wife's killer and passing it off as a simple accident which he had nothing to do with. Damn. Even better? Throughout the whole thing, there's barely a hint of hammy-ness.
She was was fairly well-known in Britain for portraying Stacey Slater in popular soap opera EastEnders. When she was cast in the third season of Being Human, many fans groaned at the prospect of having to sit through the performance of an actress largely known for shouting loudly at everyone else in the room in a soap opera. The fanbase was very pleasantly surprised when she turned in a surprisingly nuanced performance as vengeful murder victim Lia.
She also underwent quite a transformation within EastEnders. She was perfectly good as a shouter, but her last few months on the show and her character's struggle with being bipolar showed what a phenomenal actress Lacey Turner actually is.
Lotte Verbeek, Dutch actress, seen in The Blacklist is underrated but great when she's in dramas of that calibre.
Tom Wansey, in Ace Lightning. For most of the first series, people weren't convinced he knew what he was doing; then came an episode with the series first character "death". He hasn't been seen since, excluding a brief stint in a hospital drama; make of that what you will...
Radio and TV comedian Merrick Watts' TV experience was almost entirely as a host, writer and producer for his own talk/variety shows before joining The Hollowmen, but he did a pretty good job.
Ed Wynn was known for almost all of his career only as a comedic actor until his son convinced him to appear in the Playhouse 90 production of Requiem for a Heavyweight in 1956. During rehersals he actually seemed hopelessly inept at drama as he would constantly flub his lines and try to recover by falling back on his goofball style of comedy. While the network did not fire him (because Jack Palance threatened to walk if they did) they did keep on a secret understudy. Come the live broadcast, the elder Wynn gave a highly praised, heartfelt performance with any flubs flawlessly covered up with seamless and appropriate improvisation. Not only did this keep Ed's career going by proving to himself and others that he could do dramatic roles but it even prompted a television movie called The Man in the Funny Suit (starring Ed and Keenan) that dramatized the making of the Playhouse 90 production.
Brett Dalton was criticized for being bland, and being little more than a handsome face, as Ward when the series first launched. Then came the twist and his characterization suddenly had a new spark, revealing that the initial restrained persona was a deliberate choice, similar to how Anna Torv was criticized at the beginning of Fringe before she got to break loose as Bolivia. This goes double for when Ward is killed and his body is possessed by the Inhuman HYDRA worships. In just a few seconds of screen time, doing nothing but standing and looking at the camera, Dalton is able to make perfectly clear that this is not Ward anymore.
FitzSimmons were criticized early on for being little more than nerdy comic relief, until "FZZT" forced both of them to deal with Simmons being infected with an incurable disease. The two of them were highly praised for the episode, especially for Fitz' agony at watching Simmons perform a Heroic Sacrifice, even if obviously didn't stick so early in the show.
For people not yet sold on Patton Oswalt's acting, Billy furiously confronting Ward about his killing Eric really helps.
As noted above, Chloe Bennet received extremely harsh criticism for her acting in the Season 1, particularly since she played the role of the Audience Surrogate at first. After Skye got some character development, though, many critics changed their tunes and by the time she'd fully accepted her birth name of Daisy Johnson, most viewers were on her side.
Luke Mitchell was considered rather bland and uncharismatic by many critics and fans, but his emotional final goodbye with Daisy and the dignity of his final moments together with Hive received almost unanimous praise.
Although never considered a bad actress, Mallory Jansen's role in the early episodes of Season 4 was little more than standing around as a sexy emotionless robot. By the end of the season, she sold viewers on not one, not two, but four versions of the same character, all with distinctly different personalities but similar enough to feel familiar. This was especially true in the final arc of the season, where she pulled off the character's abrupt mood switches so well that her Freak Out over Fitz' rejection was considered genuine Nightmare Fuel when it could easily have come off as Narm.
Any lingering doubts anyone had about Elizabeth Henstridge and Iain De Caestecker's acting ability were obliterated in Season 4, especially during Self Control, with the scene of LMD Fitz trying to convince Jemma that he's human considered both heart-wrenching and horrifying. Taken Up to Eleven in the Framework arc when Fitz appeared as TheDoctor, an incredibly disturbing evil version of himself. Elizabeth got to show off her acting chops to believably sell The Woobie during that arc. Just try not to cry watching the scene where Simmons watches Fitz tell AIDA, he'll never love anyone except Jemma, at least until that scene takes a serious turn for the worse.
While her acting ability was never really disputed, Natalia Cordova-Buckley got to show how good she can be in the opening scene of "The End" where she nearly breaks down in front of the team over the nature of the Stable Time Loop and having to sacrifice Coulson to save the world.
Hey, remember cute, cuddly, Davy Jones-lookalike Pavel Chekov? About thirty years later, Walter Koenig did a turn as Babylon 5's Magnificent Bastard, Alfred Bester, and many viewers were shocked to discover that not only he had versatility and range, he could be charismatic, evil and downright terrifying. Reportedly, he became the envy of many other Trek alumni, for getting such a compelling and juicy recurring role.
Andreas Katsulas was a well-respected stage actor in Greece, but after his move to Hollywood was mostly reduced to playing vaguely ethnic thugs and Rubber-Forehead Aliens of various stripes. Then came the role of G'Kar, whom Katsulas played with all his might. The end result was one of the most deep, complex, love-hate-pitiable characters in television history, and firmly cemented Katsulas in the mind of non-Greeks as a true once-in-a-generation artist.
Similarly, Claudia Christian, who up until then had mostly been known for providing fanservice for the director on a budget, managed to give Susan Ivanova both strength and vulnerability in a way that made what could have been an otherwise stereotypical '90s "strong woman" into a genuinely believable and compelling character.
There was minor controversy when David Schwimmer was cast as Drill Sergeant Nasty Herbert Sobel. Notably, he was the most high profile star amongst a cast of relative unknowns. It's widely agreed that within his first scene, you forget you're watching Ross Gellar. You utterly despise Sobel for his cruel treatment of the men, and also eventually come to feel sorry for him.
Ross McCall had mostly done children's films and guest spots on The Bill before he was cast as Joe Liebgott. Not only did he break viewers' hearts in episode nine, but he also fooled most of his fellow cast members who didn't realise he was a Fake American. He credits the miniseries with helping him have a career in America.
Although Scott Grimes was reasonably known for Party of Five, he was never particularly challenged much. His HRCA moment came at the end of episode 3 when he realises just how many of his comrades have been killed. He solidified this status after the sheer heartbreak his character goes through in episode 7.
It might be shocking to realise but Damian Lewis started out as a telemarketer and had just one film and a handful of TV roles to his name when he was cast as Dick Winters. Needless to say, it was a huge success for him and remains one of his iconic roles. He claims he still gets surprised remarks from fans who didn't realize he was actually British.
Star Steve Buscemi plays very well against type as the ruthless but humane Nucky (being the star alone was playing very much against type, having been for many years a supporting actor); but it is Michael Stuhlbarg, a former bit player whose only major role was as the timed Woody Allen-type lead in A Serious Man, as the brilliant but deeply twisted Arnold Rothstein and Michael Shannon as the psychopathic Knight Templar Agent Van Alden that really leave a mark.
To say Paz de la Huerta is disliked by the majority of the fandom is putting it mildly. However, watching her performance in the Season 2 episode "A Dangerous Maid" surprised a lot of her detractors as you watch Lucy Danzinger come to terms with her pregnancy, her baby's father, and her future. It's some very deft work from Ms. de la Huerta.
Bryan Cranston is the defining example of this trope in action. Almost no one thought the bumbling dad from Malcolm in the Middle could take on such a heavy role. By the end of the series, he won four Emmys, turned the show into a critical favourite, and helped make Walter White one of the most complex characters ever to grace the small screen. His performance, on the whole, is widely regarded as one of the greatest performances in television history, with even Sir Anthony Hopkins, Hannibal Lecter himself and a surprisingly big fan of the show, referring to it as THE best acting he'd ever seen, television or otherwise. Not so surprising to anybody who is familiar with his acting resume which covers an astonishing variety of roles across film and television.
Aaron Paul was a bit actor for years with some minor film work and guest spots. Then he was cast as Jesse Pinkman on Breaking Bad and turned what could have been a thin character into a remarkably deep, fragile human being with an abundance of regret, self-loathing, a compulsive habit of destroying himself and probably the only real moral compass of anyone on the show. He won three Emmys for Best Supporting Actor, making him one of only five actors to win the respective award more than once, and one of only three actors to win it three times.
If there's anyone out there that doubts Sarah Michelle Gellar has skill as an actress, they should be made to watch the episode "The Body" and "Forever", the episode following it. They could not have worked nearly as well without Gellar's pain-stricken performance. (And she won an Emmy before she started playing Miss Summers, remember.)
Even long before "The Body," actually. Take one good look at her tear-jerking performance during her "I don't want to die," speech from the first season finale "Prophecy Girl". That was the scene for many fans that convinced them that Ms. Gellar really did have excellent acting chops.
Alyson Hannigan. She did okay in films, and looked decent in Buffy the Vampire Slayer, but the episode "Doppelgangland" was where she showed she could really, really act. Evil Vampire!Willow was darn impressive, but then Good!Willow tries to imitate Vampire!Willow, and Vampire!Willow tries to imitate Good!Willow. It was a tour de force performance. For her dramatic chops, watch the episodes "Confessions" where she is crying in the bathroom and "Wild at Heart" where Oz leaves her. She really was one of the best criers on the show.
David Boreanaz. Most people were iffy on his acting in the first season of the show and doubted he could play more than the broody sexy vampire (sexy being the key reason he was cast) but when his character Angel lost his soul halfway through Season 2, Boreanaz absolutely shined as the sadistic, terrifying, and darkly charismatic Angelus. Watching him physically and psychologically torture (and sometimes kill) Buffy and her friends was a complete 180 difference from his former self. In fact, his performance in the episode "I Only Have Eyes for You" (where the evil Angelus is possessed by the ghost of a female star crossed lover and forced to act out her tragic final moments with Buffy taking the role of the male lover) is what convinced Joss Whedon that Boreanaz was ready to carry his own spin-off show.
All of the actresses (and one actor) on Charmed at one point:
Holly Marie Combs was the unknown one of the leading actresses, though anyone who had watched her in Picket Fences would know how talented an actress she is. Her SRCA moment came in the show's second episode where she worries that she and her sisters could be evil. She ended up delivering the most consistent performances of all the leading actresses across eight seasons. Her acting range was taken to a new level with Season 4's "Hell Hath No Fury" where she loses it in front of Prue's grave.
Alyssa Milano was always considered the weakest of the actresses who played the sisters, having been known either as the child star on Who's the Boss? or for becoming a sexpot in The '90s. Her first SRCA moment came in Season 2's "Morality Bites" where she assumes the role of her future self and comes to terms with what she's become. And again in Season 4's "Long Live the Queen" after Cole has been vanquished.
Even Kayley Cuoco got this, despite her character not being well received. "Mr. & Mrs. Witch" has Billie desperately trying to get her parents to remember her and the season finale has her trying to come to terms with who her sister really is. Both are good performances from her. Though she previously showed hints of dramatic flair in the infamous 8 Simple Rules episodes following Paul's abrupt death.
Brian Krause's crying scene over Piper's body in the Season 3 finale? Absolutely atrocious and nearly ruined the scene. His crying in the Season 6 finale when Chris dies and subsequent Roaring Rampage of Revenge? He Really Can Act.
Cobra Kai: It is kind of strange that a "The Karate Kid" Sequel Series would be the thing that would let William Zabka and Ralph Macchio flex their dramatic acting chops... but they did. Boy, did they.
Joel McHale's Jeff. Jeff seems like the same "character" McHale plays as the host of The Soup. Then you see something like "Intermediate Documentary Filmmaking", and the look on Jeff's face during the following line. For context, Pierce promised Jeff would get to meet his estranged dad, whom he has issues with. Jeff said that if it turns out to be a Mind Screw by Pierce, that he will beat Pierce. Jeff is currently looking at a limo and has answered from a phone call from a man claiming to be his father and in the limo. It's obviously Pierce, and Jeff has just realized that and is right in the middle of switching between "hopeful" and "murderous rage".
Jeff: ...Go on.
Everyone on Community is amazing. It may just be the writing but Chevy Chase is incredibly funny on it. Chevy Chase. The guy who took pratfalls on Saturday Night Live for one season, did two good National Lampoon's Vacation movies and has been a punchline ever since because everything he tried either simply failed or was a complete disaster. Rebooting this guy's career is just awesome of itself.
On a related note, John Oliver's character on Community is a completely drunk version of his Daily Show self — humorously buffoonish. Then comes along "Abed's Uncontrollable Christmas", where he is so unflinchingly cruel and cynical, in one protracted voice-acting sequence, that he breaks Abed with just his words. He steals the show from a whole cadre of established actors, in one of the rawest, emotional episodes of the series, by being the rawest.
Ken Jeong managed to pull off a surprisingly convincing breakdown in "Analysis of cork-based networking when Changs "bear down for midterm slogan was turned down.
Jackson Rathbone's performance in Twilight? Hilariously terrible. His performance here in Criminal Minds? Very believable. In Criminal Minds, he played a shy, troubled, perennially mumbling, drug-addicted janitor and said janitor's split personality. What makes this even more impressive is that the other personality was a serial-killing woman with a Southern accent, contrasting with the normal personality in every possible way. To top that off, Rathbone had to transition between personalities in the middle of a scene, and he pulled that off as well.
In his first two major roles, Moonlight and Three Rivers, Alex O'Loughlin didn't impress many people (except with his hotness). But then he guest-starred on an episode of Criminal Minds as a tormented serial killer with a crippling case of OCD. His performance was incredible, and he's almost unrecognizable to someone who knows him from his other work. When you compare the withdrawn, quiet and fairly meek serial killer to his highly-physical, snarking, and aggressive Steve McGarrett he would go on to portray in the new Hawaii Five-0, the difference is astounding. Even someone who's seen both roles would be hard-pressed to recognize him as the same actor, even though the only difference in appearance is a pair of glasses.
There are a lot of surprisingly good turns for UnSubs. James Van Der Beek as a killer with three personalities, Jamie Kennedy as an unrecognisable cannibal, and Frankie Muniz as a haunted comic book artist are just three examples.
The John Nathan-Turner era was notorious for the inappropriate stunt-casting of light-entertainment figures in guest roles. How the fans groaned at the news that this was happening yet again with game-show host Nicolas Parsons being cast in "The Curse of Fenric". How the fans cheered when Parsons delivered a superb performance as a vicar trying to cope with losing his faith.
Billie Piper was viewed by many fans when her casting was announced as a has-been former pop singer, who would be incapable of keeping up with Christopher Eccleston and drag the show down. Fairly soon, even those who disliked her character recognised that she could act.
After Catherine Tate landed the role of Donna in Doctor Who, many doubted she could she'd adapt to a more serious role from her catchphrase comedy. Not only did she manage to do that, but the writers also retained elements of her notorious "Am I bovvered?" character and actually made them funnier.
Those who remember David Tennant as one hell of a Large Ham owing to his time on Doctor Who may be surprised that he's also shown his acting abilities on Doctor Who itself as well. One such example would be his work in "Midnight", particularly when the Doctor is being Mind Raped by an unknown cosmic entity. To quote the Can Only Move the Eyes page, "his reaction is shown with the barest minimum to the point where one cannot really point out any distinct facial move or change, yet he still manages to pull off enough fear and anguish to firmly cement the Psychological Horror aspect of the episode." And damn, is it effective.
Whether Arthur Darvill was any good at acting in his earlier career was mostly up for debate due to the fact that he spent most of it playing back up for a much more famous teddy bear, and now... well, watch any episode of Doctor Who he's in and you'll see what this guy can do. His conversation with Amy in "The Pandorica Opens" is arguably his best scene. This scene in "A Good Man Goes to War" shows that he can act a badass:
Rory: I have a message and a question. A message from the Doctor... and a question from me. Where. Is. My. Wife?! Oh, don't give me those blank looks! The 12th Cyber Legion monitors this entire quadrant. You hear everything. So you tell me what I need to know, you tell me now. And I will be on my way... Cybermen: What is the Doctor's message? [the entire fleet explodes] Rory: Would you like me to repeat the question?
Pearl Mackie was a relatively unknown theatre actress prior to being cast as series 10 companion Bill and some of the promotional material didn't fill the fanbase with a lot of confidence in her character. In just her first episode, the actress and the character were responded to positively.
Eliza Dushku. Most fans agree that her acting skills at the show's beginning were, while not awful, very limited. But then came the Season 2 finale in which she hits it out of the park when the realization of Paul's death finally hits her.
Alan Tudyk's breakout performance was as the nerdy, gregarious Non-Action Guy Hoban Washburn in Firefly. Then came his guest placement in the series, where he plays the Non-Action Guy to the asthmatic, scatterbrained hilt... only to bury it in an unnerving Ax-Crazy psychopath performance. No one saw it coming.
Enver Gjokaj (Victor) started out as just "that guy who can do a pretty good Russian accent." Then in one episode, they needed to interrogate a character who had been put in the Attic. For safety reasons, instead of shipping him back from where they had sent him, they just downloaded a copy of his brain into Victor. Enver was able to perfectly portray a character who had been in about a dozen episodes already. In a later episode, he gets a copy of Topher and the two snark at each other over the phone.
While his performance was never seen as necessarily bad, Steven Strait's rather stoic performance as Jim Holden was often seen as being the comparative "weak link" out of the Rocinante crew. However, his surprisingly captivating depiction of someone undergoing rapid Sanity Slippage in "It Reaches Out" was widely praised and generally seen as some of his best work on the whole show.
Wes Chatham's performance as Amos Burton has been one of the most consistently praised aspects of the entire series, with his completely convincing depiction of a near-sociopath attempting to find a moral compass being surprisingly engaging, genuinely unsettling, and weirdly endearing. Many fans have even favorably compared his "I am that guy" line from "Immolation" with "I am the one who knocks!"
While initially seen as just an unlikable jarhead, Frankie Adams as Bobbie Draper got a much better reception as Season 2 went on and she was able to show more of her own impressive acting range beyond the generic "tough guy" marine persona originally shackled to her. Praise has been especially given to her emotional breakdown upon learning of the massacre of her squad and visible shame upon realizing just how much of a skewed view she and her fellow Martians have been given of Earth.
Anna Torv received a lot of criticism during the first season of Fringe from viewers who found her "wooden" and underwhelming due to Olivia Dunham's stoic nature. The criticisms died down by the end of the second season after seeing Torv convincingly play Olivia's Alternate Universe counterpart "Fauxlivia".
The acting in Game of Thrones is superb across the board, but special congratulations have to go to:
Alfie Allen's masterful Calling the Old Man Out in the third episode of season two proves he's not just Lily's Butt-Monkey brother anymore. After that, he gets a terrifying yet tragicFaceHeel Turn, complete with excellently delivered dialogue and facial expressions showing his conflictedfeelings to his horrible actions. Then there's his performance as Reek, who despite technically being Theon, is really a completely different character utterly broken by the absolutely horrific torture inflicted on him by Ramsay. The twitching, hesitation in almost every word said, and constant look of fear in his eyes displays a man who has been through the most horrible Mind Rape imaginable.
Maisie Williams starts out as Arya Stark and has been winning near-universal praise. It's her first acting role. She had to spend much of Season 2 holding her own against the near-40-years-of-experience, highly-respected acting veteran Charles Dance. Said scenes were widely hailed as some of the best acted in the entire series.
Gwendoline Christie shows way more range in four episodes of Season 3 than in the whole of Season 2, proving that any perceived "woodenness" back then wasn't a fault on the actress' acting, but part of how Brienne really was supposed to be as a character.
After getting notoriously little to do for almost three full seasons, Art Parkinson (Rickon Stark) finally gets to show his stuff in "The Rains of Castamere", fully proving he's able to handle more dramatic material.
While nobody really doubted Kristain Nairn (Hodor's) acting ability, the character was largely used as comic relief. Then came his performance in "First of His Name", where he shows some serious dramatic acting ability, especially after Bran wargs into him to kill Locke.
Once Jon Snow began his transition into a confident and badass action hero, Kit Harington has been able to display more of his acting range. It also helps that he doesn't have to contend with the cold climate and short shooting schedules of Winter Iceland. His work in Season 5 was especially acclaimed, leading to the ending causing arguably as much fan heartbreak as the infamous Red Wedding.
Despite being a sportsman with no acting resume to speak of, Hafþór Björnsson proves himself to be more than Conan Stevens' equal as Gregor Clegane in "The Mountain and the Viper", turning in an absolutely terrifying performance. He even manages to completely bury his native Icelandic accent, which was a common uncertainty among fans.
Dean-Charles Chapman is limited mostly to portraying Tommen's childish naivety until "The Gift", when Tommen expresses his utter frustration at Margery's arrest and his impotence to do anything about it.
Prior to the series, Jameela Jamil (Tahani) was best known for being a host on Channel Four, and this was her first acting role. Her performance is just as good as her other cast members, which includes well-known comedy veterans Kristen Bell and Ted Danson.
In "Janets", D'Arcy Carden not only played her regular character Janet, but the other four cast members as Janets too. She's able to showcase their personalities and emotions perfectly. It's regarded as some of the show's best acting, and many fans were disappointed when she didn't get nominated for an Emmy.
How about Ludacris as Darius, Fin's evil stepson. He was pretty impressive as a villain and honestly stole the show as a legitimately intimidating perp.
SVU is apparently good for this sort of thing. Witness Carol Burnett (yes, that Carol Burnett) as Birdie Sulloway in Season 10's "Ballerina" and Kathy Griffin, (yes, that Kathy Griffin) as Babs Duffy in Season 11's "P.C."
Another odd case is Cynthia Nixon. While she is a good actress, and no one's arguing that she's best known at this point for Sex and the City, a show with a reputation for being a little vapid and superficial. When she goes on SVU, she plays a woman with multiple personalities and jumped from one personality to another easily (and horrifying people who only knew her as Miranda).
Even before Ludacris, there's Ice-T himself. While he'd been seriously acting for a few years, most of his roles were drug dealers and gangbangers, which people probably didn't see as a stretch for someone known primarily as a gangsta rapper. There were a lot of raised eyebrows when he appeared on screen to play Fin Tutuola, with jokes about the rapper who brought you "Cop Killer" playing a cop. And then he proceeded to own the role.
There was also Schuyler Fisk, best known as Sissy Spacek's daughter and the girlfriend in Orange County playing a college student who has a child with her estranged father. Talent clearly runs in that family. (Acting aside, Schuyler is also a really good folk-pop singer as well.)
Danny Pino was no slouch on Cold Case, but it's really impressive how well he's taken over the spot vacated by Chris Meloni on SVU. Love him or hate him, Stabler was central to the show, and the fact that Pino came in and blew right past the Replacement Scrappy box is truly a feat.
Kate is certainly among the series' more divisive characters, but there's no doubt that Evangeline Lilly has turned in some excellent and heartbreaking performances. Special mention goes to the episode "Whatever Happened, Happened." - her quiet sobs as she leaves baby Aaron with his grandmother are sure to tug at the heartstrings even if you don't care for Kate.
While Michael Emerson is often ranked among the best actors for creepy, scheming villains, Lost was the show that revealed just how much DEPTH he could bring to them. His performance as Benjamin Linus is so good that when he cries for the first time after his daughter is killed, you feel genuinely sorry for him even though it was kind of his fault. The nuance in his acting as Ben goes from puppeteer to puppet is just remarkable, and then the sheer loneliness and brokenness he conveys in the final season makes it all the more satisfying when he finally redeems himself. Boy did he EVER earn those four Emmy nominations.
Maggie Grace's Shannon Rutherford is usually considered among Lost's less likable characters, but she does have some great scenes that show she had real potential. Special mentions go to the scene where she tries to shoot Locke in her grief after Boone dies and the episode "Abandoned," where we get flashbacks explaining her insecurity and her toxic relationship with her stepmother.
Jorge Garcia is consistently hilarious and lovable as Hurley, but he can also make you cry like a baby when he needs to. One of the finest examples of this is the episode "Dave", in which Hurley struggles with his self-loathing and comes to believe the Island is a figment of his imagination. The scene where he tells Libby that she wouldn't have feelings for him if she were real will just make you want to hug him.
Colin Morgan and Angel Coulby easily dominated the early episodes of Merlin, especially with their character's reactions to their girlfriend and father's deaths respectively, but Bradley James gets to prove himself with Arthur's rage against Uther and subsequent meltdown when he discovers the truth about his mother. Angel and Bradley also deserve credit for completely and utterly selling the Arthur/Guinevere romance, a relationship that even the shippers admit was initially a bad case of Strangled by the Red String.
Katie McGrath was often considered the weak link amongst the younger cast considering she was the only one who had no professional training, but she manages a heart-rending delivery of the line: "I'm scared, Merlin," and nails a later scene in which Merlin is forced to poison her, in which she goes from confusion to gradual realization to horror and panic without a single word of dialogue.
It's pretty common for fans to be blown away when seeing Colin Morgan in a serious role for the first time — he's never bad as Merlin, but in Island and Parked, his two subsequent film roles, he's phenomenal to the point that after having gone to see either film specifically for him, it's easy to be so drawn in to his performance that you forget that it's him.
Overshadowed by the others, but definitely worth a mention is Santiago Cabrera's performance in the episode "Lancelot du Lac". He had only appeared in five episodes prior, and while he does play a very good Lancelot, he completely and utterly nails a Soulless Shell of Lancelot in this episode. No Psychotic Smirk, no Obviously Evil behavior, but he just subtly and slowly creeps you out until the end of the episode when seeing him throws off the Uncanny Valley. The last scene where he is revived for a few seconds on the funeral boat shows just how different the two characters were.
While we're at it, everyone in the episode "Lancelot du Lac" was great. The scene where Arthur confronts Gwen over her infidelity is so painful to watch that the recap of the episode doesn't even write it down, just links you to the scene.
Jared Gilmore of spent most of the show playing a ten-year-old boy with a lot of plot importance, but not a lot to actually do. He wasn't bad, but it wasn't an acting challenge either. Then came the episode "The New Neverland", where he was possessed by Peter Pan. His bone-chilling delivery of Pan's cold, remorseless words did a great deal to convince fans of his acting talent. And those that needed more convincing were won over by "Operation Mongoose".
Rebecca Mader usually just had to show up, be rather hammy and throw in a few trolling comments as Zelena. But in the second half of Season 5 during her romance with Hades, and particularly in "Sisters" she shows Zelena's Hidden Depths and turns in a very genuine performance.
Critics were, at least at first, somewhat split on whether Jim Caviezel as John Reese was any good, however, it's pretty much universally agreed that his performance in "The Devil's Share" as a grief-stricken and dying John desperate for vengeance after Carter's death was terrific. He also gives a brilliant performance in the series finale. His desperate cry of "HAROLD!" when Finch is preparing to sacrifice himself is extremely affecting, especially considering it's one of the only times in the series that he raises his voice.
Michael Emerson is usually considered an excellent actor — for villains. So, therefore, many were surprised to see that in POI, Michael's character HaroldFinch would not only be a protagonist, but the borderline moral center of the series, and understandably, many had doubts as to whether he could pull it off. They were so very, utterly wrong. Michael's wise, empathetic and vulnerable performance feels COMPLETELY different from, say Ben Linus or William Hinks. And then you get to Season Five, where Harold is forced to abandon all of his personal rules in order to keep Samaritan from taking over the world. He's absolutely chilling, and it adds a whole new layer of depth to Harold, proving that Michael can bring weight and complexity to good guys, bad guys and everything in between.
Sarah Shahi, a former NFL cheerleader who sadly hasn't been given many acting roles that truly show her off, joined POI in Season Two as Sameen Shaw, who has an Axis II personality disorder. This means two things: A- she's barely capable of sympathizing with others, and B- most of the time her voice is somewhat monotone. This is actually quite difficult to play convincingly, and in the hands of lesser performers and writers, Shaw could have been a very thin character. But Sarah rises to the task, gradually making Shaw a bit more human every season. And she has some truly great material in the fifth season. First, there's "6,741", where Shaw finally escaped Samaritan's clutches, and in an absolutely heartbreaking scene, commits suicide rather than having to kill Root or give away the team's hideaway. Then it's revealed that it's only a simulation. When she really does get back, she's struggling with PTSD and is terrified that it's just another simulation. Sarah's crowning moment, in the final episode, is a simple one. When Fusco tells Shaw that Root always thought her disorder made her beautiful and that she never thought she needed to change, she doesn't sob, but rather, sheds a quiet, single tear. She clearly knew her character inside and out.
Kevin Chapman as Lionel Fusco at first only gets to be a bumbling jerk, but, as he redeems himself and becomes a part of the team, it's shown that not only can be a genuinely funny and charming presence but also a heartbreaking and powerful one. Perhaps his crowning achievement is Fusco's speech to Simmons after Carter's death.
"That's just it. I could've been just like you, a bottom-feeder who turns on his own kind. For what? Money, power? I got lucky. I had a partner. She was good for me. For a lot of reasons. She reminded me that I could be good again too. I could be a good father, a good friend. A good cop. I'm not gonna let you undo all the good she did. Carter saved my life. She...she saved me from myself. Because she believed in me. And I'm not gonna throw that away on a piece of crap like you."
Power Rangers is actually pretty good for these moments. Considering that one of the prerequisites for being a Ranger is being a "Teenager with Attitude" (or at least a young adult), you end up with very young people who are doing their very first big job and have little experience otherwise. It could be said that they become good actors because of their time on Rangers.
Amy Jo Johnson is probably the best-known example of this trope. There's a great moment from the second season of the original show when Kim is kidnapped by Goldar and is turned into his perfect bride... which happens to be Rita Repulsa. The potion doesn't take, but Kim decides to mess with Goldar, Squatt, and Baboo and turn in a pitch-perfect imitation of Rita, right down to the screeching and "I have a headache!", enough that Goldar thinks it worked too well. Even Linkara mentioned in his review of the series that this moment is scarily good.
Melody Perkins jumps in leaps and bounds from her first appearance as Astronema in Power Rangers in Space. In her first few appearances, she chews and hams more than the previous season's villain Divatox, including a great amount of Shatner speech. A few episodes and she'd gotten better, and then came the epic 'Secret of the Locket' arc, where she portrayed Astronema teetered between good and evil so well that the viewer honestly didn't know where she would end up in the end. And then, after turning her back on being a bad guy, she is downright terrifying when she is reprogrammed back into her Astronema persona.
Regardless of how you feel about Power Rangers Operation Overdrive, the scene where Mack finds out he's really a robot is well-acted. You can just hear the grief Mack and his father feel after learning and admitting the truth, respectively. Also from the same series, Ronny's sadness after Mack supposedly dies is pretty jerking as well, even if it only lasts for a few lines.
Power Rangers Time Force is an absolute gold mine for acting moments. Jen's reaction to seeing Wes for the first time is one of only many.
Power Rangers Dino Charge has a lot of these moments, being on the better side when it comes to acting. Still, the knightly speeches of Ivan or the charismatic (and hammy) attitude of Heckyl take the cake.
Saturday Night Live: A huge chunk of politicians, musicians, and athletes have hosted the show and proven themselves to be very skilled comedians in addition to their day jobs.
Caroll Spinney in the episode about Mr. Hooper's death. Spinney absolutely nails it as he perfectly communicates how a little kid like Big Bird struggles to come to terms with a dear friend's death.
While the particular scene isn't online as of this writing, there was one episode where Big bird decided to accept that the adults were right and Snuffy wasn't real, so he had to say goodbye. The two bid a tearful farewell until Big Bird realizes his feathers are wet from Snuffy's crying, so he has to be real. According to Spinney, he and Jerry Nelson (the actor who played Snuffy at the time) were both actually sobbing in their costumes.
He is able to play several completely different in personality characters in Smallville. There's Clark Kent, Kal (Clark while infected by Red Kryptonite, a hedonistic and insensitive Jerkass), Kal-El (Clark Kent's Straw Vulcan Kryptonian self), a teenage Jor-El during flashbacks, Bizarro (who gets Character Development into a Woobie, Destroyer of Worlds), and Clark Luthor/Ultraman (who's screwing his own sister). And when Clark gets possessed, he perfectly copies the person's speech patterns.
You can even see how Tom Welling improves as an actor by the different personalities he portrays on the show. Kal and Kal-El seem a little over-done and forced when he portrays them, but his Clark Luthor is so different from the normal Clark through subtle acting differences and a more reserved portrayal. Clark Luthor is probably one of the most disturbing things on the show; he looks like Clark, but Welling portrays him completely differently whilst simultaneously avoiding the viewer thinking "this is just the guy who plays Clark doing him another character" — we are absorbed into the role.
The same can also be said for his co-star Michael Rosenbaum as Lex Luthor. While he was never bad in the series (quite the opposite, in fact), it was the Season 3 arc when Lex is desperately trying to win his father's affection by doing increasingly terrible things that really showed how much he had grown. When he crosses the line into full-on villainy, it's both terrifying and heartbreaking. He shows how horrible a person Lex can be while reminding us of the boy he used to be. By the end, it is practically impossible to imagine anyone else playing the role.
Michael Shanks gets several chances to act as someone other than Doctor Daniel Jackson (actually, Daniel ends up with other people stuck in his head almost as often as he ends up dead, come to think of it), and the performances range from chilling, to heartbreaking, to hilarious.
Christopher Judge also has a couple of instances where he gets to do something other than Teal'c being a stoic badass. The highlight is definitely the incident where Teal'c and Jack end up switching bodies, and he nailsRichard Dean Anderson's mannerisms.
All the child actors in Stranger Things, some of whom had never acted before or had very little acting experience.
While she proved her chops as early as the pilot, many agree that the scene where an enraged Kara is using her Heat Vision in full power to destroy Red Tornado, while flashbacks from her last moments with her parents were being shown, is where Melissa Benoist has really won the crowd.
After nine episodes with little to do besides having a vaguely creepy crush on Kara, Jeremy Jordan gets far meatier material in "Childish Things" when Winn has to deal with his criminal father, and his fear that he'll turn out the same way.
Tyler Hoechlin was met with no small amount of scepticism when he was announced to be playing Superman in Season 2, mostly because fans felt he wasn't large enough to play the burly superhero, and partly because he was a popular fan choice to play Nightwing instead. People started being more optimistic about the casting when The CW released a two-minute long sneak peek before the season premiere. Then the Season 2 premiere aired, and few people cared anymore about his perceived lean look and he was hailed as an optimistic and friendly Superman done right in the modern age. People started demanding that the network start working on a Superman series starring him before the episode was over. (And indeed, a Superman and Lois series was announced to be in development in 2019.)
When it was announced Jon Cryer was taking the role of Lex Luthor, lots of people were outright confused, since he's better known for sitcoms. He'd played Lex's comic relief nephew Lenny in the infamous Superman IV: The Quest for Peace, and stated he had taken the role partially to atone for that. But when he finally appeared, he managed to play the character at a level equal to or even surpassing Michael Rosenbaum's take on the character (see above), especially his Magnificent Bastard tendencies. He even managed to become a major character during Crisis on Infinite Earths (2019).
The quiz broadcast sketches also show the acting skills of the pair of them (and Sarah).
Z Nation. Not so much for the actors, but for the company. It's a decent TV show made by The Asylum, a studio typically known for producing So Bad, It's Good Mockbusters, and films with intentionally cheesy premises like Sharknado. While the special effects are still bad, the fact that Z Nation is both well written and acted is completely unprecedented.