Penny: [as Spock] We have studied your son Sheldon from the 23rd century... His unique genius is our only hope of bringing peace to a vast and troubled galaxy... *beat* [as herself, prompting] Sheldon, it's you. Sheldon: Oh, I'm sorry, I just love that line.
As the name implies, a Self-Insert Fic is one where the author has made a simulacrum of him- or herself — commonly called an avatar — in the story's world as a key character. If the author has any sense of subtlety, the resulting character won't share their name or alias, but it's still easy to tell who that "new character" is.
The self-insert is very often a Mary Sue — in matter of fact, the original Mary Sue (she who gives that trope its name) was born from a parody of the standard Self-Insert Fic. In the most extreme cases — which are usuallybut not always quite bad — the insert character gains some degree of godlike power, or retains considerable knowledge of the series in which he's been inserted, or both, and uses them to adjust things to his or her liking. In rare instances, it might work well — especially if the people in the setting — heroes and villains — react accordingly to the new situation and the guy that knows all the stuff he saw in the (anime/game/etc) and the situation changes in ways the character can't anticipate.
However, equally common is the subversion, where the main character applies This Loser Is You to themselves and ends up as The Ditz, The Fool, or in extreme cases a Butt Monkey. Care must be taken to not still make themselves more important than anybody else, lest they just end up with an Anti-Sue. The main rule is to never put the character in a high-ranking story position, although they may be the narrator.
The Self Insert has two primary varieties: the Self as New Character, where the author simply opens the top of the story and drops a copy of themself right in, and the Self as Existing Character, where the author finds himself forced to take over the life (and sometimes the body) of an existing canon character — without necessarily being restrained to staying "in character" for their new role. See Possession Sue for the latter.
Note that self-insertion isn't automaticallybad. After all, there's nothing wrong with a little Wish Fulfillment — Provided that the author remembers to insert their flaws as well as their fantasies. Just as not everybody loves and adores a person in real life, they're not all going to love and adore them in a fanfic, either. Self-insertion, complete with flaws and realistic reactions from everyone involved, is just as good a way to make an Original Character as any other. What was originally a self-insert can even adapt and evolve into a genuine Original Character.
The trouble is that many new writers don't think about that. They think only about ways in which their Author Avatar can be perfect, can within minutes hook up with the sexiest character available, cure their faults, force their beliefs on others, and ninja-kick their way to being the hero, rather than working on a realistic way they can enter the plot.
Played for Laughs this can become almost a different story entirely, which usually involves an average loser realising that whatever fictional world may not be the best or safest place for them, and commenting on the implausible things going on.
See also Life Embellished, Author Avatar, Write Who You Know, Her Codename Was Mary Sue.
Played with in Dreaming Of Sunshine - the Author Avatar is not godpowered and, in fact, attempts to change the timeline as little as possible. This is actually justified, as she is attempting to retain her advantage by not rendering her knowledge of future events useless. This is difficult, as she arrived many years before the worst of the shit starts to hit the fan. She has some skills beyond the norm, but those stem from being reborn with her memory intact, not from being an Uberninja.
Nine times out of ten, a new original senshi in any Sailor Moon fanfiction will be a self-insert, replete with godlike powers and totally authority over everyone and everything — the girl is usually related to a canon character as well. Considering the show's target audience was teenaged girls, which then became 5-13 girls when the show hit the US, this is not surprising.
In "Zenith, Darkness, Reverie", the author admits to basing the protagonist and antagonist on herself. The teenaged, female protagonist acquires a Death Note. This should be a humorous, fangirl-esque tale, right?
Kali can barely manage coherency in Part 2 due to Kira's intervention, veers into disturbingly serene sesquipedalian monologues frequently, and is psychologically shattered. Kira is amused.
Jared "Skysaber"Ornstead is known for his deliberately over-the-top self-insert character Skysaber, an interdimensional superspy-troubleshooter who was actually apotheosized into a literal god during the course of The Bet.
His current (August 2007) project is a "type two" Self Insert called ''My Gilded Life'', in which he has found himself taking over the life of Gilderoy Lockhart right at the end of Harry Potter and the Philosopher's Stone; with his knowledge of the books he is deliberately and relentlessly running roughshod over canon.
The authors of Undocumented Features started the project in the early 1990s as a self-insert fic for themselves and many of their friends, but as time has gone on, the focus has moved mostly off their avatars and onto other, newer characters (including some of their avatars' kids).
Many other EPU projects also involve self-insert avatars, making it one of their signature details. However, even though their Neon Exodus Evangeliondidn't include either of the two primary writers as insert characters, critics still accused the story's lead of being one or the other in disguise. (Arguably this protagonist, DJ Croft, is a Marty Stu. But he's not an avatar.)
NXE manages to invert the Author Avatar trope with John Trussell. He was inserted in the story before he became one of the authors.
SIs are pretty common in Neon Genesis Evangelion fandom. Especially the female body swap kind... either a spare body of one of the show's main characters, or some OC with an even more fucked-up past than the series' own characters. Unfortunately, these are considered the good ones. New Perspective Evangelion by Dartz_IRL and I was a Teenage Dummy Plug by Foxboy. The second of these is usually regarded as the best of the subgenre.
The reason why this works so well is in canon there are a bunch of soulless bodies just hanging around in the depths of Terminal Dogma.
Gregg "Metroanime" Sharp also subverts the self-insert trope with his fictional counterpart "Grey", who becomes a cosmic Butt Monkey doomed to endless futile struggle in an uncaring multiverse.
Contrabardus a.k.a. Carrotglace has also played with Self Insertion, but usually with a somewhat more comedic take than Metroanime. See his stories The Spirit Within, Insertion, Insertion: Reflux! and Gaijin (though this last is anything but comic).
Possibly the most infamous example of the godlike insert is Darren "Twister" Steffler and his incomplete mid-1990s megaseries Twisted Path. Steffler's work started out rather crude but improved noticeably as he continued writing, although it never quite reached better than high average in quality. Nevertheless, Twisted Path was incredibly influential, prompting a number of other writers to create their own Self-Insert or pseudo-Self-Insert fics, many of which included Shout Outs to Twisted Path or blatantly set themselves in the same multiverse◊.
One such story was Bert Van Vliet's The Bubblegum Zone, a Bubblegum Crisis self-insert which later had an explicit crossover with Twisted Path in the latter series' fourth installment.
Another is Ed Becerra's Legion's Quest, which carefully and skillfully walks the complicated line between playing a godlike Self Insert straight, parodying it, and subverting it. It, too, crosses over explicitly with Twisted Path, in its own Bubblegum Crisis segment.
Possibly the most notorious self-inserter of all was the one known only as "Oscar"; his Author Avatar was a 13-year-old Super Saiyan hermaphrodite (no, that is not a joke) who engaged in a sexual affair with Artemis from Sailor Moon... in his cat form. (Again, that is not a joke, as much as one might wish it so.) In later stories, Oscar became "involved" with Felicia from Darkstalkers and Lola Bunny. To top it all off, the real Oscar then mysteriously disappeared, and is now presumed dead. A link to anMSTseries of some of his work; linking to the actual stories would be NSFW.
Dr. X of Suburban Senshi is a surprisingly well-done self-insert, even with his gobs of power that mix and match multiple canons. It's all in the writing (and the fun social commentary, upon which the series could stand alone).
Not A Dirty Word by Michael Fetter is a rather... twisted, parody of the usual Type 2 self-insert, in which the male author finds himself stuck in the body of Kasumi Tendo of Ranma One Half — and finds he has to abide by her "rules of behavior". His efforts to find loopholes in those rules, and the repercussions his successes have on the established plot, are what really make this a fun story. Just, please, ignore the utterly cringeworthy prologue describing Jesus getting mad at the author and punishing him with the insert.
Speaking of Ranma ½, fanfiction written in the mid-90's commonly featured Self-Insert Fic, but with amusing twists due to authors trying to avoid the pitfalls of this trope. The most common twist was usually the author being deposited in the fic wholesale, with no changes from their real self, and the story characters teaming up to reap gallons of pain on the author for the things they've "put them through".
Tom Dyron is one of the more audacious, unbelievable examples readily available. His 13-chapter fic, Evangelion 2: The DELTA Invasion (EVANGELION 2!), is the most ridiculous mess ever seen. Tom, the character, is... look, just read it. MSTed in the link above, do not attempt to read it raw.
David Gonterman's fanficseverything feature Gonterman himself (or an obvious Author Avatar) as the story's real hero. In the rare cases he isn't, it's because he made an obvious dream heroine, whose boyfriend will be suspiciously similar to him.
One might consider this blanket statement to be nullified by Gonterman's insert in Planeswalker being the father of the main character... if it weren't for his lax attitudes about incest coming to the forefront of Sailor Moon: American Kitsune... yeah...
Crazyeight'sFourth Wall series is set in a fanfiction website that is a place in its own right, accessible to authors the way the Digital World of Digimon is accessible to the Digidestined, except they only need to log on to visit. The first in the series, The Wages of Fans is Fiction, is about an author who tries to replace the Digimon canon with his own fiction and the resulting revolt, with other authors leading the revolutionaries in person.
Hundreds, possibly thousands of these came up over the years in the Bob and George forums among the fan authors. It would be impossible to list them all. Needless to say, some were good, some were bad, and some were just plain ugly.
Oh! My Brother. An example of the good kind of self-insert fic. Christopher Angel manages to create a very readable and enjoyable series.
The Multi-universal crossover Sleeping with the Girls deconstructs the idea of a self-insert heavily. The idea is that every time the nameless self-insert falls asleep, he is teleported to the bed of one of eight girls from anime. The problems quickly build up, as a) most of these girls are Tsundere types, and do not react kindly to him. b) "comical" attacks like a Megaton Punchwill kill the Self Insert and subject him to the Chunky Salsa Rule. c) Because he has to wake up as quickly as possible to avoid the aforementioned consequences of death at the hands of crazy girls, by the end of the first volume, he has gone almost a week without sleep, is badly injured from a vast collection of wounds accumulated from a variety of sources, and the healing nanobots he picked up in his first world nearly boil him alive in his own sweat. d) because of his actions, he has severely damaged the timeline of several worlds, possibly dooming them.
Boy Scouts ½ (readable here) is a Ranma ½Elsewhere Fic that follows an original group of characters, many of whom are based on the creator of the series and some of his friends from Boy Scouts. Some of the other real people included in the stories also went on to write for the series, as well. Notable in that, while not always entirely successful, the creator of the series tries to avoid in jokes and make the series somewhat accessible to any reader, even if they do not know the real people involved, or if they are not very familiar with the series that inspired it.
Boy Scouts ½ takes things further by having a spin-off series called Perspectives, which began when the main author of Boy Scouts ½ gave three friends he had made on the internet brief cameos in Boy Scouts ½, part 11 and one of those friends then began authoring a series following those characters, making it a self-insertion spin-off of a self-insertion fic!
Very common in Fruits Basket fics. The character will usually be one of Tohru's long lost relatives or a twin of of the zodiac members (to explain why they turn into the same animal). If it's a girl, her love interest will most likely be Kyou.
The One Piece fandom is full of fanfics about the cool new member of the Strawhat crew. Variations include fics about a cool new pirate joining the Whitebeard/Red-Haired/Heart/Kid Pirates... you get the idea. These are so prevalent that subversions and deconstructions of such stories are beginning to become a sub-genre of their own.
Ebony Enoby Dark'ness Dementia Raven Way, of My Immortal infamy, is a thinly-disguised self-insertion Black Hole Sue in an unrecognizably goth (and poorly written) Harry Potter universe. The author, Tara Gliesbie (or Gillespie, her spelling skills are notorious) only saw the movies, and only became aware of the books at around chapter 15 or so ... not that she has any respect for the movies' canon either. The other characters occasionally slip up and call Enoby "Tara", thus giving away her nature as a self-insertion.
When challenged to write a shameless self-insertion in the Harry Potter fandom, Sam Storyteller went the 'godlike powers and meta knowledge' route. The end result was a touching guardian angel style piece which may just have turned the genre on its head.
The hero of The Takers is two-fisted action-adventure writer Josh Culhane. The book is written by action-adventure writer Jerry Ahern, who deliberately gives the character some of his own traits.
Many Harry Potter fanfictions feature an 'American exchange student' (in a British school), who happens to have a main character fall in love with them and be friends with everyone (even the Slytherins). No reason is ever given behind the exchange, nor do any Hogwarts students ever go over to America..
Live Action TV
Not surprisingly, a fair amount of Star TrekFanfic follows this line, including any number of stories where, due to painfully contrived circumstances, Mr. Spock falls passionately in love with a woman who bears an astonishing resemblance to the author. The term "Mary Sue" actually comes from A Trekkie's Tale, a parody of these kinds of stories.
I Carly: There is copious amounts of this usually by having a new transfer student that just happens to have the same name as the author joining the same school as the iCarly Power Trio. They also usually end up in a Love Triangle with them all.
The Professional Wrestling internet fanbase loves this kind of fiction, often called "Dynasties", "Legacies", "Diaries", or just plain "Fantasy Booking".
The whole concept of taking a wrestling company and shaping it as the author sees fit doesn't necessarily have to be Self-Insert Fic material, but when the story opens with Vince McMahon handing over control of the family business to a total stranger, the tone is irreversibly set. (And don't start on the number of women's wrestlers who get into romance...)
In 85% of wrestling fanfic these days The Undertaker ALWAYS has a daughter in her early-twenties who, of course, falls in love with [insert name here but it's usually Randy Orton].
Almost as common is a girl showing up as Matt and Jeff Hardy's long-lost sister. This will not necessarily stop her from sleeping with one or both of them.
Parodied extensively in the British comedy show Garth Marenghis Darkplace. The show is based on the premise that Garth Marenghi wrote and starred in a 80s low-budget hospital-based horror show. Many jokes are based on the idea that Garth Marenghi not only wrote the series, but also plays the central role in the show. As such, his own character — Doctor Rick Dagless, M.D. — exhibits outrageously unrealistic traits.
MAGIC VOICE: Warning! Unauthorized use of self insertion! JIM: Cram it, you talking tin can! MAGIC VOICE: You're out of line, mister— eep! JIM: Hahahahahaha! I'm invincible!
A famous, and often ridiculed, Marty-Stu among Doctor Who fandom is Ben Chatham, a character who very strongly resembles his creator (the legendary Outpost Gallifrey / Gallifrey Base poster sparacus), sharing his manner of speech, his political viewpoints, even his taste in drink. Even the suggested actor for this character is an actor that the author has admitted to fancying. Needless to say, around 90% of characters in each story instantly fall for Chatham.
A rather large percentage of other fanfics featuring an author-created companion for the Doctor could arguably fit in this trope quite comfortably as well.
A good chunk of SupernaturalFan Fic contains self-inserts that are supposed to be the Winchesters' sister, who is either a long-lost relative or just always been there.
There was a case of a DM adding himself in the background of the Inn the PCs were in as a joke. One of the PCs decide to kill the DM. The DM then decided to spend the next few minutes describing how all of existence was ending except for their characters as they had killed the person who created their entire world.
Kingdom Hearts is somewhat notorious for its terrible self-insert fictions, mostly starring young fifteen year olds who somehow get sucked into their television sets and get keyblades.
Mixed Bag Comics is a Sprite Comic using characters from, well, as many sprite-based games as possible. Some of these characters appear to act as if in their original continuities while others don't and yet more do so only partially, making the position of the self-insert seem less out-of-place than it would be otherwise. The webcomic twists the trope even further in several ways:
The Author Avatar and the narrator are two distinct characters who both play reality-bending parts in the story.
Neither the author nor the narrator, despite being reality-benders, are the most powerful characters in the story; there are godlike programmers that are more powerful reality-benders than both the author and the narrator, and both have been trumped several times by regular characters as well.
The author not a very important character, but he isn't so unimportant that he's just an occasional cameo. The author is pretty much on equal terms with the rest of the cast in terms of importance and shifts out of the focus of the comic as often as any of the other regulars.
A less Stu-ish example comes from Toy Hammer with a direct self-insert (down to name, appearance and personality) in the form of Vincent, a friend of the main character (a reclusive artist named Michael). There's a slight piece of Fridge Brilliance in there when you realize that both Vincent the author and Vincent the character both literally 'drop off' Michael into the story (via creation then by car), but otherwise that's the only mention of him for the first ten chapters of the story. However, he does become a surprisingly competent fighter (for an unfit gun-geek) and later a Supporting Leader.
My Inner Life has the blatant self insert Mary Sue of Jenna Silverblade. Hilariously, the author actually freely admits that Jenna is "herself" (or rather an alternate version of herself who lives in Hyrule when she sleeps) and gives a huge disclaimer at the beginning that because of this, she believes the fanfiction to be true to some degree.
This category of fanfiction is very common in Touhou. Average Joe In Bullet Hell is a semi-straight example, in which the traits of the author are passed to the protagonist, Ryan Randa.
Another well made example of this trope could be Mass Vexations, whose protagonist, Art is actually a fan of Mass Effect, which he loses repeatedly and ends up trapped in, making him Genre Savvy to the point of Medium Awareness, justifying his status as a nail in the Mass Effect universe even when he doesn't invoke it himself. While Art ends up in a relationship with a canon character, their relationship progressing at a realistic rate, only becoming official 20 chapters in to the fic's Mass Effect 2 version, more than two years after they met.
Over Mass Effect's Fan Fiction archive, there are much more Fem Shepard fics than Male shepard ones, at least 3 times more. Just to get an idea, there are 6.6 thousand romance fics, 4.4 thousand of that (exactly 2/3) are about Fem Shepard.
Done in the Devious Four Chronicles (a well known Super Mario WorldROM hack series) with the characters of Hunter and SCORPION, villain versions of their respective authors about whom the entire plot is based. But then you had the works released a bit earlier when the group consisted of four different authors... which meant every game had literally four major characters that were Author Avatars of their authors. Leading to such 'interesting' situations as Randor Land 3, the game raocow played when each world had a different self insert character seemingly appear from nowhere to take a shot at Mario and co. You can see a great example of the result in this raocow video.
Neo's Happy Funtime Land by Neo The Saiyan Angel is an excellent parody of a Self Insert, in which the author rewrites an episode of Kim Possible and secretly tricks the animators and voice actors into producing it. The author describes herself as an "absolutely gorgeous person..." for a paragraph or two. Neo goes so far as to change a character's hair with the snap of her fingers, saying that she liked it better blond.
In the Animaniacs fanfic A Horrible World of Plot Holes and Spelling Errors, the author inserted herself into the fic. Dot immediately recognized her as "that bitch who had me strangled to death by a drug addict on Christmas Eve". Since the fic was a parody of current fics, the Warners encountered no less than three Mary Sues (two of which were hopelessly in love with Yakko), spelling errors galore, and a crazed fan of Dot. The Warners go to the author to see what was going on. She explained that it was a parody of Mary Sues and the role they play.
As much as the artist denies it, the infamous Disneyfan01's even more infamous Mary Sue, Marina Seadrift, is very much an idealized Self Insert. Disneyfan01 readily admits to actually being in love with Long John Silver from the Disney bomb Treasure Planet, and Marina, in a webcomic called Faith of the Heart, which incorporates elements of Treasure Planet with the world of Square Enix's Kingdom Hearts, is deeply in love with a severely canon-raped Silver. They two eventually consummate their relationship, which is, thankfully, not shown too graphically, thanks to the artist's personal distaste for drawing nudity.
The character of Peter Chung in Mike Wong'sConquest; his academic and ethnic backgrounds are similar to those of the author's, and when analysing Imperial technology, he even brings up some of the same points made on the main part of the site.
There's a picture floating around the Intertubes of director Mitsuo Fukuda and writer Chiaki Morosawa cosplaying as Kira and Lacus, respectively, from Mobile Suit Gundam SEED. When you watch the last third of Mobile Suit Gundam SEED Destiny, that image starts to take on somewhat sinister overtones.
Blood Red Dragon may have taken this to absolutely new heights... or lows. The entire story is based on a self-insert of Yoshiki Hayashi and a model, at least at the beginning.
When Marv Wolfman was writing The New Teen Titans, he gave Wonder Girl an older boyfriend (who was, apparently, one of her college instructors). The new boyfriend, named Terry Long, was breaking up with his wife who looked like an older version of Donna to marry the hotter, younger, super-powered version. He was also an insufferable jackass in his earlier appearances. For some reason, the artist, George Pérez, drew Mr Long to resemble Marv himself. Undeterred by fan Squick, Marv had Donna and Terry marry; afterwards, Terry developed into a nicer, more decent, more tolerable character.
Once Wolfman had left the book, one later writer had Donna and Terry divorce, and then a Wonder Woman writer killed off both Terry and the son he'd had with Donna in about one page.
The most important of the THUNDER Agents is Leonard Brown, AKA Dynamo, a studly hero who could tear apart tanks and had to deal with the attentions of several beautiful women, including the sexy villainess Iron Maiden. The name of his original writer? Len Brown. However, Dynamo differs from many self-insert characters in that he has concrete limitations on his powers, as he couldn't use his Thunderbelt for more than thirty minutes at a time. He also had the advantage of being drawn by Wally Wood. (Also, it turns out that the character wasn't named Leonard Brown when Len Brown created him: the editor renamed him for the lulz.)
One of the (two) screenwriters for the B-MovieSoultaker (which is best known for being featured on Mystery Science Theater 3000) also played the lead female in the movie. The plot? A rich girl and her ex-boyfriend get into a car accident and must outwit an angel of death, who was in love with her in a past life. Hmm...
Charlie Kaufman wrote himself into the script of Adaptation, a movie "adapted" from the book The Orchid Thief. The movie is about him trying to adapt The Orchid Thief, and eventually writing himself into the script.
The wild thing is that he manages to go the This Loser Is You route as well as the (well-written) Mary Sue route by inventing a fictional twin brother Donald who is everything Charlie is not. He even goes so far as to list Donald Kaufman in the actual credits of the film alongside himself, meaning that he was the first fictional character to be nominated for an Academy Award.
From the liner notes to Peter Brooks' screenplay/stage version of the Mahabharata: Since Bhishma has renounced woman, Vyasa is asked into the story to sleep with two princesses. He does so, although the princesses shrink from him, since he is dirty and smells. (Vyasa is the in-universe poet who narrates the Mahabharata in this version.)
Edmund Morris's 1999 biography Dutch: A Memoir of Ronald Reagan was a somewhat controversial case of Self Insert Non-Fic. Morris chose to insert a semi-fictional narrator named "Edmund Morris" into his biography of the 40th President.
Richard Marcinko, former Navy SEAL, has written the Rogue Warrior series, a collection of anti-terrorism action novels with himself as the main protagonist. What is especially interesting is that the fictional Rogue Warrior books are written as sequels to the factual first book, entitled Rogue Warrior, which was Marcinko's autobiography. What is even more interesting is that his real life exploits (leader and founding member of both SEAL Team Six and Red Cell, along with being a legitimate Jerkass Stu) make it almost impossible to draw a line between self-insertion and avatarhood. Fans and critics of the series argue over whether Marcinko's characterization in the fictional followup books is blatantly overpowered or whether he is, in fact, just that badass.
FBI agent Joseph Pistone, better known as Donnie Brasco, wrote (or put his name on top of) several fiction novels following him going undercover yet again as Donnie Brasco to infiltrate some evil goings-on or another. These seem to be out of print.
A rather blatant example, the post-apocalyptic novel Warday, by Whitley Strieber and James Kunetka, follows the authors as they travel the country five years after a nuclear war, making a study of postwar America. The characters only differ from the authors in that the characters have been through a nuclear war.
It has been argued that Left Behind by Tim La Haye and Jerry B. Jenkins, is biblical Fan Fic where the two intrepid, studly, and irreproachable leads (Rayford Steele and Buck Williams) are transparent MartyStus for the authors and their personal ideologies.
"very fair-skinned, with long, straight, dark brown hair and chocolate brown eyes. Her face is heart-shaped — a wide forehead with a widow's peak, large, wide-spaced eyes, prominent cheekbones, and then a thin nose and a narrow jaw with a pointed chin. Her lips are a little out of proportion, a bit too full for her jaw line. Her eyebrows are darker than her hair and more straight than they are arched. She's five foot four inches tall, slender but not at all muscular, and weighs about 115 pounds. She has stubby fingernails because she has a nervous habit of biting them."
However, in the books, Bella is given so little physical description (or depth of character) that she is in many ways the ultimate in self-insert Mary Sues, because any girl reading it can slide herself into Bella's place (assuming she's not just reading it for the lulz). Meyer flat out said that she "left out a detailed description of Bella in the book so that the reader could more easily step into her shoes."
There's also the fact that Edward is Stephanie's own Relationship Sue, having at one point stated that if an actual Edward Cullen came along, she would leave her husband and children without a second thought.
Halfway between fanfic and literature, in the Beekeeper's Apprentice we are introduced to Mary Russell. It is unrevealed whether her middle name is Sue, but Mary is a Sherlock Holmes fan who runs into the aging detective in Sussex (at a point after where the Conan Doyle stories end). Mary eventually gets a degree in theology and marries Holmes. She is of course written by an author who is a Sherlock Holmes fan with a degree in theology. However, the series is written by a professional author and you can buy it in bookstores.
Clive Cussler writes himself into every one of his later Dirk Pitt novels, either overtly (with him stating his full name to Pitt at some point) or slightly more subtly (His initials, for example). He generally appears for the sole purpose of assisting the main characters in their adventures, who never manage to remember him, though they do find him familiar on occasion.
Even when Cussler himself doesn't appear, he inserts himself another way sometimes. One example is Professor Beaty in Night Probe!, who bears a distinct resemblance to Cussler.
Sometimes, if he doesn't appear, he'll give some extremely minor (as in, only mentioned once) character his name ("the notorious bandit 'Big Foot' Cussler") This isn't a self insert per se, but nothing beats the time Clive Cussler inserted Bruce Springsteen guitarist Nils Lofgren into a novel (not in his guitarist capacity though).
Older Than Print: In The Divine Comedy, Dante is the author Dante Alighieri with a heavy dose of Wish Fulfillment: he gets to see his real-life enemies burn in hell, interact with famous people he admires, reunite with his real-life lost love Beatrice who turns out to have loved him so much that she set up this whole journey to save him, and ascend all the way up to Heaven to see God up close. That said, he's not as bad as most examples of this trope because he's not idealized or talked up as a paragon of masculinity and the books are more about the places he journeys through than his heroic deeds or specialness.
In the Redwall Series, Gonff from Mossflower was supposedly based on the author, Brian Jacques. That the later book Doomwyte deals with Gonff's descendants probably has something to do with this.
An example of a very good Self-Insert Fic is Charlotte Bronte's Jane Eyre. Like Jane, Charlotte was a governess to the children of Constantine Heger, a married man who she was "lonely" and "homesick for" when apart from him, and "attached to" when she was in his company. No crazy ladies in the attic at the Heger home, though. Jane's strong moral character and love for/ambivalence towards the rules set forth by God were also very much a part of Charlotte's personality. Self-Insert Fic can be cool!
Christopher Paolini, author of the Inheritance Cycle has stated that his main character Eragon started out as a fantasy version of himself doing things the real Christopher could never do (i.e. being a Dragon Rider). However, he also says Eragon eventually developed into his own character and is no longer this.
It's tough to say whether it counts as Mary Sue or autobiography, but either way Rivella in 17th century proto-novel The Adventures of Rivellais the author, Delariviere Manley.
J.K. Rowling has said that Hermione Granger is the closest to a Self-insert character, being partially based off of her own childhood self.
James Joyce's A Portrait of the Artist as a Young Man and Ulysses have a self-insertion character by the name of Stephen Daedalus. He isn't the most sympathetic character. Considering that Portrait is, more or less, Joyce's autobiography (as the title makes rather clear) or at least his telling of his coming-of-age story, and that Ulysses is its sequel, this makes sense. More interesting is that, although Stephen is quite clearly an Author Avatar, he shares more personality traits with Joyce's brother rather than James himself. Then again, this is according to the brother
The protagonist of Philip K Dick's VALIS, Horselover Fat, is heavily based on the author. ("Horselover Fat" is a rough translation of "Philip Dick", from Greek and German for his first and last name respectively.)
Wayne D. Barlowe made himself the main character in his book Expedition.
Sammy-Jo Strauss doesn't even try to hide it in her self published book, From Reality to Fiction, considering the main character shares her name.
Stephen King appears as himself in two volumes of The Dark Tower. He is by no means a sympathetic character, and is disliked by the ka-tet. He is also literally their creator, making him a rather supreme example of an Anti-Sue.
The villain of Those Who Trespass is suspiciously similar to author Bill O'Reilly. The hero also shares O'Reilly's background and the personality he claims to have in his nonfiction books, but is not as obviously meant to represent O'Reilly himself.
Rhonin, a character appearing often in Warcraft novels written by Richard A. Knaak, is highly regarded as an insertion sue. His exploits ranging from saving the red dragon aspect from an orc warlock of greater power to going back in time to help win an ancient war (that had already been won, who knows why he felt the need to put himself in it) to banging Sylvanas' other sister that never existed until Knaak decided he needed some elf ass.
The Interpretation of Murder: A murder mystery about a turn of the 20th Century New York detective, who enlists Freud's help to solve a murder and gets to hang around with Freud, Jung and Brill discussing psychology and Hamlet... written by a New York lawyer (Jed Rubenfeld) with an undergraduate degree in psychology who wrote his thesis on Hamlet. Still a great book though.
The Greenwich Trilogy: written by three different authors, and each book stars the author who wrote it, and has the others as secondary characters. The first book was nominated for a Hugo Award in 1968, which definitely shows that this trope is not necessarily a bad thing.
Zoey from The House of Night is a essentially a more perfect version of Kristen Cast. According to Wikipedia, they based the character on her so she would be easier to write. Yeah...
Live Action Television
No less a luminary than David Gerrold originally wrote the famous "The Trouble with Tribbles" episode of Star Trek to feature a young ensign that he saw as a self-surrogate, and did something similar in his novel The Galactic Whirlpool. The former was an attempt at literal self-insertion, since Gerrold, an amateur actor, wrote the character of Ensign Freeman in hopes of getting to play the role himself. The role instead went to Paul Baxley, William Shatner's stand-in (which is why O'Brien mistook Freeman for Kirk in Deep Space Nine: "Trials and Tribble-ations"). But Gerrold did get to appear as a background crewman in "Tribble-ations."
The foreword to the Doctor Who 2009 Specials box set is, in fact, a short story by David Tennant wherein he goes back in time thirty years to tell his eight-year-old self that he will play the Doctor someday. In other words, it's a double-self-insert RPF. (And yes, it's adorably geeky.)
On The Big Bang Theory, Sheldon wrote a Star Trek fanfic when he was a kid, about how a little kid from Texas is taken away by Mr. Spock to join the crew of the Enterprise.
This is the basic gimmick of Secret Girlfriend. The main protagonist is you. He's never referred to by name and never says anything out loud, but all of his friends adore "you." All of the jokes (which you're basically supposed to insert) are hilarious. All of the girls want you and you end up with most of them. You would probably feel awesome if not for your two friends being total idiots and your ex-girlfriend being a Yandere.
Ryan Murphy has a history of creating characters for him to function as Author Avatars, but he has finally come to this with The New Normal where the character of Ryan is a successful creator and showrunner of a teen musical show called 'Sing!', has a loving, hunky, manly boyfriend and the only character who hates him is a homophobe.
The My Name Is Earl episode "Creative Writing" has the main cast writing self-insert stories. Most of them blatant Mary Sues (complete with superpowers and ninja); one writes a soap opera, and another writes a musical number.
Singer and Nirvana frontman Kurt Cobain's widow Courtney Love pretty much admits that Princess Ai is a very loose and much more fantastical version of her life. That is, if the fact that the title character works as a singer, falls in love with a "sensitive musician" named Kent, and has a name that means "love" in Japanese or Chinese didn't tip you off.
This is the actual power of Bleach's new post-timeskip villain Tsukishima. To those not affected, it's Invasion Of The Bodysnatchers-level disturbing to see their friends greet him as if they'd known him all their lives. Especially for Ichigo, when he learns that Tsukishima Marty Stu-ed himself into everything he has fought and suffered for.
50 Cent: Bulletproof and its sequel 50 Cent: Blood on the Sand. According to The Other Wiki, when asked to do the voice for the main character of Grand Theft Auto: San Andreas, 50 Cent replied that he would only voice himself in a video game. So these little self-insert adventures were developed for him.
This trope is literally invoked in the Kingdom Hearts series with the 100 Acre Wood. Thanks to the magical nature of the book (it sucks the reader from the "real" world into the story), restoring the Pages (and thereby reconstructing the world) and interacting with the characters, allows Sora to (inadvertently) rewrite the plot of Winnie the Pooh to include himself as a prominent character (replacing Christoper Robin). When you lock the world's keyhole, it even includes him on the cover with the rest of the characters.
In-universe example: The fifth arc of Umineko no Naku Koro ni is largely a Self-Insert Fic written by the main villain, whose Author Avatar hijacks the story from the usual protagonists and proceeds to wreak havoc on the plot and characters.
Sakupen in Dadgame is probably a parody of this played for laughs (his power is really over the top, plus he runs away screaming when first engaged) which does not stop him from being atrociouslyhard.
The Lord Of The Rings The Third Age's story is about a group of people who act like a shadow to the original Fellowship of the Ring. They go to the same places and witness simillar events in the movie. They even help the original team fight off Balrog and the monster army in Helm's Deep.
The Alien Crossfire expansion to Sid Meier's Alpha Centauri includes a faction editor. You can use it to add a pre-created faction into the game called the Firaxians with either Sid Meier or Brian Reynolds.
In the XCOM: Enemy Unknown remake, entering Sid Meier's (or one of the members of the design team's) name as a soldier grants you a maxed-out soldier, although the game considers it a cheat and disables Achievements.
The Sultry Argonian Bard (introduced in Skyrim) is a gender-flipped version of The Lusty Argonian Maid (introduced in Morrowind, over two hundred years earlier). The name of the female character is the same as the author's (the author of Maid at least bothered to slightly modify his name).
SCP-423 is literally named "Self-Inserting Character," a non-corporeal entity named "Fred" who can add itself as a minor character into stories printed on paper. Normally the character plays a background role, never very important or causing changes to the story. However, it was noted that when placed inside it's own SCP article, the only thing that changed was the addition of "ruggedly handsome" at several points.
The Simpsons: Marge practically inserted herself into her own novel, but she didn't stop there, she more or less inserted the entire residency of Springfield into the story. Initially she writes Homer's character as a noble, loving husband, but when the real Homer commits a brazen display of Jerk Ass-edness, Marge angrily rewrites his character to match. The real conflict comes when Marge has her protagonist fall for Ned Flanders' character, making everyone in Springfield suspect that Marge had fallen for Flanders. When Homer actually got around to reading it, he went after Flanders... not to kill him (unlike the novel), but to ask him for advice on how to be a better husband. As for the novel, it got terrible reviews but sold well enough for every person in town to have a copy of it and the Olsen twins even recorded a dramatic reading.
An episode of Samurai Jack had Aku tell fairy tales to the children of earth in hope of showing them his side of things and making them more obedient minions when they grow up. This eventually ended up with him turning every protagonist into himself (WITH GREAT FLAAAAAMING EYEBROWS!) and every antagonist into Jack.
In the Futurama episode "Where No Fan Has Gone Before", the entity known as Melllvar has written a script for an episode of Star Trek: The Original Series, where he saves the crew of the Enterprise, and has Uhura tell him how attractive he is. He then holds the cast prisoner, and forces them to act it out.
Koenig(as Chekov): "'Look, Keptin, it is Melllvar. I wope he will welp our vessel.'"
Mellvar(angrily): "'WESSEL!' You're not acting hard enough!"
In the My Little Pony: Friendship is Magic episode "Spike at Your Service", Rainbow Dash claims to be writing a novel about an "awesome Pegasus who's the best flyer ever and becomes the captain of the Wonderbolts!" Rarity is quick to point out that Dash may be basing the plotline on her own aspirations.
The fic Martian Manhunter turns the concept of the Self-Insert Fic on its ear, along with the Fusion Fic. Veronica Mars finds herself, along with her supporting cast and backstory, shoehorned into her favorite TV show, Buffy the Vampire Slayer. It plays out as a self-insert fic, and yet it isn't.
Similarly, Ma Vie Et Roses by Scott Johnson and Scott Jamison subverts and plays with Self Insertion. In this Revolutionary Girl Utena fic, an anime fan finds himself shoved into a show he's barely even heard of. One of the authors, who was genuinely unfamiliar with the series at the time, wrote the actions of the pseudo-Author Avatar Skyler Sands, while the other wrote the rest of the fic around him. Acting out of true ignorance, Skyler manages to thread his way through the main action while still ranging far afield (such as ending up joining the Shadow Girls' avante-garde theatre group). Skyler is very Genre Savvy, which helps (but not enough), and eventually ends up speculating on the existence and motives of the "meta-Skyler" who put him in the story.
Self-Extraction: a "charming little tale of the people who write themselves in, and the people who shoot them back out", written round-robin by a half-dozen or so authors. Initially played for laughs but gets more serious toward the incomplete ending.
The Wild Horse Thesis has Ranma Saotome inserted via magic spell into the shoes of Shinji Ikari of Neon Genesis Evangelion by Gosunkugi in the hopes of getting rid of him. Unfortunately for the caster, Ranma uses his situation to his advantage, and proceeds to wreak havoc on Gendo's plans for to change the ending of the anime for the better. One of the better examples on this page, it was good enough to earn a place on the Fan Fic Recommendations listing.
Discussed in the TRON fanfic A Whole New World where the game Tron 2.0 is presented as a creation of Encom employee Jet Bradley. Clu implies that the only reason for that game to exist is that Jet wanted to make a Self-Insert Fic with himself as the Mary Sue character.
Done in a cute manner in the Friendship is MagicFanficCadance Of Cloudsdale. As Princess Cadance tells a young Twilight Sparkle a bedtime story, the subject of her tale is a young princess who was taken in by her aunt princess after her kingdom disappeared, and is sad with her situation but is happy when she gets to foalsit a wonderful filly. Even as a filly, Twilight knows who the princess actually is.
Hivefled has the young trolls posting to Conscription Fiction.com, a site for really bad real-person fic about themselves and their teachers. Ganmed Lomust posts fic about his "Mayree Tseouh" hanging out with the Grand Highblood, and Lieutenant Gritch contributes to the round-robin fic his students write about killing him horribly; nobody's sure if he's trying to be funny or trying to make them stop.
One minor character in the Hawk & Fisher novels was a self-promoting mercenary who wrote loads of over-the-top adventure stories about his own "incredibly heroic deeds", then published them as mass-market chapbooks under a pseudonym.
In Ultra Fast Pony, Pinkie Pie writes a The Lord of the Rings fanfic in which "the brave and sexy Pinkie" joins the Fellowship of the Ring, and later winds up in a love triangle with Bill the pony and Shadowfax.
Historical example: Given the state of the facts, Martha Jane Canary-Burke, aka Calamity Jane herself, may be the world's first fangirl to create Self-Insert Fic - her claims of relationship to Wild Bill Hickok and serving under Custer are largely unverifiable or false by history. She was known as Calamity Jane because most of her lovers ended up on Boot Hill.
Anna Leonowens (the "I" in The King and I) exaggerated her role and influence at the court of the king of Siam, though not to the extremes her erstwhile "biographers" did in the works based on her own.
It's said that creating characters involves taking a part of your personality, exaggerating it, and letting it become its own person, so as to make a realistic character. If that is true, then most characters would at least be partly this.