This kid has barely started puberty, but acts as if always preoccupied with responsibility. He (or she) works hard at whatever he does and treats things seriously, but every once in a while he does indeed act like a kid (and hates the subsequent teasing). Usually not taken too seriously by anyone and hates being treated like a kid by adults, even if they secretly like the attention.
Often his family situation is problematic, although he may have a big sister or brother he respects and admires. Said sibling may not appear (letting the audience take that role) and the Adorably Precocious Child can attach to the closest adult who lets him — this is especially common if he's also a Mouthy Kid. Sometimes this works in reverse, and the adult character may have to defend himself against unwholesomecomments by other characters by insisting they're Like Brother and Sister, or, alternately, Older Than They Look. If they grow up, they're likely to become hot, especially if they had a Hot Dad or Hot Mom, due to the Generation Xerox effect.
Compare Cheerful Child, Innocent Prodigy, and Wise Beyond Their Years. Sometimes also a Token Mini Moe.
open/close all folders
Anime and Manga
Former Trope Namer Shotaro Kaneda from Gigantor, or, as he's known in the United States, Jimmy Sparks, so embodies this trope that he's the trope namer for both this andShotacon.
His cousin Hiro might also count, being an actual middle schooler (Momiji is a high-schooler who looks like a middle schooler) who is clearly much more responsible than his mother and gets extremely offended any time he thinks someone is treating him like a child.
Momiji also grows up in the manga. Of course, Fruits Basket being a Shoujo series, he just becomes a Bishounen. He retains his personality, though.
Negi of Mahou Sensei Negima! (pictured above) was the basic polite version earlier on in the manga, while Kotaro Inugami is more of a Mouthy Kid. Both of them, however, are extremely capable on their own. Due to Genre Shift and liberal use of magical age-up pills, Negi has this trope more or less beaten out of him by various physical and emotional trauma by the midpoint of the story, although he hasn't been broken of the habit entirely.
Rurouni Kenshin: Yahiko. Turns into more of a Cute Bruiser by the end of the series, to the point that he gets his own sakabato and a lot more responsibility in the epilogue.
Mamoru Shimesu in Phantom Quest Corp. He actually runs the company, the contacts, the finances, etc. while his boss Ayaka spends their funds on booze. He has a very stressful job.
Though he's 13 (and then 14), Riku from Blood+ looks younger. He also acts much older, too.
Hitsugaya Toshirou of Bleach also seems to suffer from this, except that a lot of people in the story do treat him seriously, because he's in a position of authority. Although he's Really 700 Years Old, he still suffers from this because the rest of the characters he works with are even older.
Jim Hawkings in Outlaw Star, who is clearly the more mature of the group between him and his "aniki" Gene.
Naota from FLCL, an entire series based around him trying to act adult (to be a good Replacement Goldfish for his big brother) and being mocked for lapsing into childish behavior.
Shingo Tsukino from Sailor Moon is like this (when he's not slipping into Annoying Younger Sibling mode). He's highly intelligent, more mature than his sister, and manages to charm quite a few ladies over the course of the series (both older and younger than him).
Czeslaw Meyer of Baccano! deliberately tries to cultivate this image, despite being Really 700 Years Old. He claims he isn't used to being treated any other way.
Revolutionary Girl Utena's Mitsuru Tsuwabuki, who is constantly bending to Nanami's every whim and taking care of her business, takes the desire to be treated like an adult to extremes - his rants during the Mikage Seminar and his duel with Utena border on the Ax Crazy. "I want to become an adult and wreck the whole world! Wreck it!" "You become an adult by destroying other adults!" Or something to that effect.
13-year-old Wataru from Hayate the Combat Butler fits both the acting hard-working and responsible (he does pretty much run the head branch of his family's video rental franchise) and Mouthy Kid aspects of the trope. He doesn't have a big sister, although his maid Saki does fill the role.
If Hayate wasn't just a bit too old to qualify, he would probably be the poster-child of this trope. The levels of Moe that boy radiates are staggering.
Usso Evin in Victory Gundam, who is the second youngest Gundam protagonist at the tender age of 13 but also lived mostly alone and takes care of/is friends with the even younger 11 year old shakti. He hijacks a mobile suit mid-air singlehandedly for himself, and has to be blackmailed (in a way) to pilot the titular Gundam. In a aversion of this trope, people only make fun of him when he's being childish since whenever he's being serious... well, it's not funny.
Boo from Now and Then, Here and There is adorable, loyal, protective, loving, responsible, mature, kind, innocent (but not for long), and realistic. He's also a child soldier, forced to fight in a mad king's army. The responsibility on his shoulders is staggering. Doesn't have a Cool Big Sis, but latches onto the series' Ensemble Dark Horse, even taking a bullet for him.
Sayonara Zetsubo Sensei has Majiru, Nozomu's nephew, who looks to be around 7-9 and sorta looks like a mini version of Nozomu. A bit snarky/mouthy, but still cute. He's not actually responsible for anything, but he acts very mature and sophisticated for his age. And he & Kiri Komori seem to be developing feelings for each other.
Shippo in Inuyasha is the equivalent age for a young kitsune and, despite being a crybaby at times, often takes delight in being more emotionally mature than Inuyasha himself.
Black Butler: Ciel Phantomhive is a more dark take on the trope. The reason he acts serious and mature is the trauma he endured through losing his parents, and being kidnapped and tortured by cultists. He's now a driven, if jaded, Earl and owner of his own toy and candy company while he searches for the culprits in said torture.
Sui Takishima, from Special A. Seeing as his big brother is basically perfect, it takes some persuasion by Hikari before Sui decides to actually do something. Once he does, however, he's almost as stuck up as Kei.
Hanaukyo Maid Tai. Taro is only 14 years old but tries his best to act in a responsible manner as head of the Hanaukyo family, including looking after the maids' welfare. Although the maids technically are under his orders, they at least influence what he does most of the time and sometimes (as in head Security maid Konoe Tsurugi's case) try to order him around.
Makoto from Wandering Son is only around 9 at the start of the story but is remarkably mature for his age, even compared to the other characters.
11-year old Takashi from Nicoichi is not only adorable but as a result of his fine upbringing, also very responsible and can easily lead an independent life by himself.
Ken in Powerpuff Girls Z is one of these kids, and is swings from being a Child Prodigy to being plain Adorkable, and the three Powerpuff Girls will often treat him like their cute younger brother (though they are not related to each other). Ken is an only child, living with his father (Professor Utonium) in Tokyo Laboratory, while his mother is an astronaut on the International Space Station.
Chiyo from Azumanga Daioh. She's always in a good mood, very childish and cute as a button... yet also always knows the answers, helps her (high school) classmates, and is more mature than many of them.
The Phantom Menace: Cute? Young? Super-Serious? Doesn't like to be treated like a kid? Family problems? Relationship with an older girl? Anakin Skywalker! Only in the first prequel, since Attack of the Clones takes place around ten years later and he's grown, well, quite a bit.
Older Than Television: The trope goes at least as far back to the detective novels of Edogawa Rampo (1894-1965, real name Hirai Tarou), whose protagonist Kogoro Akechi was frequently aided by the "junior detective" Yoshio Kobayashi. According to Wikipedia: "Kobayashi was written as a perfect young teenager who, some might say, had a strong 'dependency' on Mr. Akechi. Every time he appeared, he was either worried about Akechi's well-being or helping Akechi set the trap for criminals. On the numerous occasions that the boy was captured, Akechi swooped in for a timely rescue."
Rare Western literature example - Eoin Colfer's book The Supernaturalists involved a 'kid' called Ditto who was Really 700 Years Old - okay, in his early twenties - but as he was a naturally-immature adult he occasionally cracked.
Eoin Colfer also brings us Artemis Fowl, who at the beginning of the series is a twelve-year-old evil genius who plans to rebuild the Fowl family fortune using fairy gold.
Markl from the movie of Howl's Moving Castle. He's generally more mature than his mentor, Howl, and yet still young enough to freak when a girl threatens to clean his room.
Better yet, Howl's child disguise in the new sequel, House of Many Ways, fits this trope to a tee, as not only does he speak with an exaggerated lisp, but also is described to be ultimately cherubic with golden curls, adorable puppy-fat, and a lot of lace. It's even more ridiculous when his reasoning for adopting a jailbait disguise is simply because he had a horrid childhood (or so he says, Sophie immediately denounces him as a liar) and he has every right to relive being six years old... only prettier. But because it is only a ruse, he manages to surprise the main character, Charmain, into speechlessness when he drops all pretenses and acts very adult and down-to-business.
Olver from The Wheel of Time fits this trope in-universe despite being described as downright ugly in the books. It probably has to do with when he follows his Big Brother Mentor Mat around to watch his back and tries to mimic the Warders.
Doctor Sweets of Bones definitely qualifies. He's the youngest member of the team and cannot get himself taken seriously because of it, tends to lapse into Sophisticated as Hell mid psych-babble, looks up to the two main characters as Parental Substitutes, and is all around Adorkable.
Nicki Reagan on Blue Bloods is in middle school, but dresses and behaves like a thirty-two year old. She isn't cowed by any of the Reagans, regardless of age, and seems to view herself as the matriarch of the family.
25th Baam from Tower of God, a cute young boy with a talent to befriend people and who really wants his best friend back. He is very diligent, honest and compassionate, extraordinarily humble and talented. JyuVioleGrace on the other hand…
Taro of Disgaea 2 is a fairly straight example, though a bit of a Cloud Cuckoolander. He's sweet and more mature than one would expect and is absolutely adorable. He's not taken very seriously by anyone, though.
There's also Emizel in Disgaea 4, although extremely young (for a demon), he's attempting to fill the role of Grim Reaper for his father. People don't take him seriously at all, but that's more because he's terrible at his job than his age. He's also clearly being played for cute, thanks to his bow tie and shorts.
Ken Amada from Persona 3 seems like a typical one of these at first. He acts unusually mature and serious, and isn't taken all that seriously by the older party members. However, it's later revealed that he joined SEES so he could exact revenge on his mother's killer.
Culotte of La Pucelle. He's generally much more mature than his Promoted To Parent big sister, and hates being treated like a child. He's also adorable.
Jr. from the Xenosaga series plays with this trope. He's certainly set up to be a typical precocious child, acting far more mature than his tender years would suggest. However, he's generally taken seriously by everyone he meets, and we later learn he's actually pretty immature for his age, seeing as how he's chronologically in his thirties.
Link definitely qualifies. None of his reincarnations are older than 16, some as young as 12, but he has no trouble taking the whole "fate of the world" thing in stride.
The professor's boy assistant Luke Triton from Professor Layton. Acts mature? Check. Isn't always taken seriously? Check. Played for cute? So very much check.
Shinra from Final Fantasy X-2. He's a kid genius and often the least emotional of the Gullwings. A bit unusual in that he is wearing a suit that covers him completely, including his face.
Pierre from Harvest Moon would be an almost archetypal example, between his cute, childish appearance, and his mature, sophisticated behavior... Except for that fact that no-one ever fails to take him seriously, even though he looks younger than every other character that's not explicitly a small child. Making this weirder, he's also an Expy for an especially grotesque Gonk.
Alfred, the adorable younger brother to Maya and a member of the rival gang of Drifters in Wild ARMs 3. He's clearly more mature and level-headed than his impulsive, treasure-seeking sister.
Hope of Final Fantasy XIII becomes this with character development. Although played for cute all along, he's a Bratty Half-Pint at game open, but he's become very mature for his age by the time the game ends.
Riku from Kingdom Hearts was extremely perceptive and insightful at five years old, able to immediately spot an off-worlder and give Sora outstanding advice about a complicated issue.
Bugsy from Pokémon, one of the youngest Gym Leaders in the series, but also one very dedicated researcher. And while he's always deep into his research (bug Pokemon in the game, ruins in the manga), he sometimes shows a very child-like enthusiasm about what he likes. It also adds to his charm that he's often confused for a girl.
Another adorable and confusing nerd is Rief from Golden Sun Dark Dawn. While his age is ambiguous, his appearance, voice squeaks, and behavior all suggest that he is on the young side of Golden Sun's traditional Kid Heroes.
Thirty years prior to them in Golden Sun: The Lost Age, Eoleo was a dorky-looking toddler too young to talk, but not too young to fake crying to throw off attention, experiment with his new Psynergy powers, break his father out of prison, and reason that Felix can solve the traps in Treasure Island that had the pirates stumped. And when addressed telepathically through Mind Read, he had a perplexing case of Little Professor Dialogue.
Caillou from Recettear is a good example of this trope. He's a powerful mage, running a serious investigation, but inside he's still just a kid who can't resist candy.
Carl Clover from BlazBlue, despite being just a kid, he's a vigilante that has captured many criminals with the help of Nirvana. He always talks in a very professional matter and dislikes being treated as a kid. His attitude does hide a rather vulnerable side of him, though.
Tricks from Scruff is a Talking Animal version of this trope, being a young Border Collie pup with an easygoing, smart, modest but playful personality.
The titular character of Hey Arnold! OWNS this trope. Acts as if he's preocupied with responsiblity, once had a crush on an older girl (well, she was only two grades ahead), and one of the most adorable kids on the show.
Mimi and Scooter are no slouches in the cute department, either. Mimi usually pushes her authority on Scooter, who wants to launch head on into the episode's unsolved crime.
Yugo from Wakfu is one of the most emotionally mature, yet earnestly childish examples of this trope.
Most of the male KND Operatives in Codename Kids Next Door ironically do quite a few things things you'd expect adults to do (usually when non-villain adults aren't around to notice) and yet the show still maintains the fact they're kids, given the KND is a military organization consisting entirely of children (with some areas in science, politics, etc.) so that would in ways make sense. Oh, and the boy KND Operatives are really adorable, just ask their fangirls.
The titular characters of Phineas And Ferb, especially Phineas. Baljeet as well.
Robin from Young Justice, though he's thirteen and technically juuust outside of the proper age range. But since he's the youngest and the most experienced crime fighter of the six main characters, the effect is pretty much the same. See also: Billy Batson.
Amberley of The Dreamstone, despite often a Hero Antagonist, has clear shades of this at times. She's noticably more intelligent than Rufus and unlike him, seems to hold down her job rather competently. At times however, her bratty temper flares and she acts twice as rambunctious as him.
Subverted by Ruth Lawrence, a child prodigy who at nine succeeded in passing the advanced examination in pure maths that British school pupils do not normally do before eighteen. While she became the youngest undergraduate ever at Oxford University, it was noted that her brilliance in mathematics did not confer special maturity on her, and in all other respects she was a markedly opinionated ten year old girl who was hard for other undergraduates to relate to, and could on occasion be disruptive in a way the university was not equipped to handle. (While Ruth was undoubtedly precocious, she certainly was not adorable: fellow undergraduates went so far as to call her "obnoxious"). Oxford has since reviewed its policy for making such exceptional admissions.