The Trope Kid

In The Wild West, a man had to grow up fast if he wanted to survive. Quite a few gunslingers and outlaws made their reputation before they were even old enough to shave regularly. Thus, they got "Kid" as part of their nickname. Given the lethality of their professions, few lived long enough to have this become an embarrassing name.

The naming convention is referenced in settings outside The Wild West as well, particularly in Professional Wrestling.

See also Young Gun.

Westerns

 * The Cisco Kid.
 * Rawhide Kid, the Two-Gun Kid, the Ringo Kid (not related to John Wayne's Ringo Kid in Stagecoach), the Apache Kid, the Arizona Kid, the Prairie Kid, the Texas Kid, the Western Kid, the Gunsmoke Kid, the Dakota Kid and (in a slight variation) Kid Colt, all from Marvel Comics. According to Stan Lee, Marvel publisher Martin Goodman loved Westerns, and was particularly fond of this trope for some reason.
 * The Time Wars book The Six-Gun Solution had a time-traveling character acquire the nickname "The Montana Kid".
 * The babyfaced Audie Murphy played youthful outlaws and adventurers so often that he joked once that he'd "kidded his way through the movies." Relatively few of his thirty-plus western characters have The Trope Kid nicknames, though: Billy the Kid in The Kid From Texas, The Cimarron Kid in the film of the same name, The Silver Kid in Duel At Silver Creek, and The Utica Kid in Night Passage.
 * The Schofield Kid in the movie Unforgiven.
 * The Sundance Kid from Butch Cassidy and the Sundance Kid.
 * DC Comics character the Wyoming Kid.
 * Might count under Parodies as well, but in Shanghai Noon, Jackie Chan's character is listed on a wanted poster as "The Shanghai Kid." His partner notes, "That's a really cool nickname, too." Jackie's character immediately complains that he's not really from Shanghai.
 * In a possible Shout-Out, Jackie Chan Adventures featured a Flash Back to a suspiciously familiar-looking ancestor of Jackie's in the Old West nicknamed "The Hong Kong Kid". Amusingly enough, Chan is from Hong Kong, so the cartoon comes one step closer to Real Life.
 * The Sundown Kid of Live a Live.
 * The Ysabel Kid from J. T. Edson's Floating Outfit series.
 * Fee 'The Kid' Herod of The Quick and the Dead
 * The titular character from The Durango Kid, played by Charles Starrett. Between 1940 and 1952, there were 64 movies made featuring the Durango Kid.
 * In Little Big Man, Jack Crabb is known as the Soda Pop Kid during his "gunfighter period".
 * The Brimstone Kid from Youngblood Judgment Day. He was a gunslinger who sold his soul to the devil in exchange for unbeatable gunslinging skills.
 * Robert E. Howard's 'The Sonora Kid'.

Non-Western

 * Professional wrestlers "The Heartbreak Kid" Shawn Michaels, 1-2-3 Kid (later known as X-Pac),the Dynamite Kid, etc.
 * Troper Tales: Heart Burn Kid and Eponymous Kid.
 * "Kid Death" from a series of pulp short stories was a Gangster variant on this trope, so called because of his youthful appearance and the tendency of corpses to appear whenever he was around -- not all by his hand.
 * Death the Kid from Soul Eater, and his Gunslinger ways are clearly inspired by this idea. He is the son of the Grim Reaper too.
 * Stephen King's novella, The Colorado Kid is not Western, but rather a semi-detective tale.
 * And his book The Stand had a character known just as "The Kid".
 * Superheroes: Invisible Kid, Karate Kid, Kid Quantum, Star-Spangled Kid, Kid Flash, Kid Eternity, Kid Devil, Kid Omega, Kid Vulcan, Kid Marvelman Miracleman...
 * The Cincinnati Kid
 * The Heartbreak Kid (1972 film, remade in 2007)
 * Also the name of a 1985 song by Restless Heart actually called Back To (The Heartbreak Kid)
 * Eyeshield 21: Musyanokoji Shien, the quarterback of the Western-themed Seibu Wild Gunmen, is usually only referred to as "Kid". Also an Ironic Nickname, since he has an old man's face.
 * Elvis Presley's boxer character in Kid Galahad.
 * The Cold Steel Kid, Gus' video game character in Deadly Games.
 * The Sundown Kid in Live a Live.
 * The Coca-Cola Kid

Parodies
"Moe: They called me Kid Gorgeous. Later on, it was Kid Presentable. Then Kid Gruesome. And finally, Kid Moe."
 * In a Mad Magazine parody of Fantasy Island, the Tattoo stand-in was supposed to spread the fame of a guest's character as "The Babyface Kid", but picked a lower body part to feature instead.
 * The Waco Kid from Blazing Saddles.
 * 'Kid Shelleen', a gray-haired drunk (but still a gunfighter) played by Lee Marvin in the 1965 film Cat Ballou.
 * Cat in the Red Dwarf western episode: "They call me the Kid ... the Riviera Kid."
 * The "Toronto Kid", in a Kids in The Hall sketch.
 * Detroit-based Faygo soda pop had a series of '50s commercials featuring "The Faygo Kid".
 * Nestle has a long-running series of ads for its white chocolate Milky Bar featuring 'the Milky Bar Kid'. The Milkybar Kid is strong and tough, and only the best is good enough...
 * The Myth Adventures novel Little Myth Marker, being a parody of gambler tropes, gives us the Sen-Sen Ante Kid (he always includes a breath mint in his stake for good luck). Subverted in that he's an old fat guy who got the nickname a loooooong time ago.
 * From The Simpsons, when Moe described to Homer his boxing career:


 * The long-running children's show Wonderama had a dance contest segment in the '70s that was introduced by "the Disco Kid," a boy in a Lone Ranger style Western costume.
 * The Rumpo Kid in Carry On Cowboy.
 * Whose Line Is It Anyway? The names of "Weird Superheroes" often dip into this trope.

Real Life

 * Billy the Kid
 * The Sundance Kid
 * The Apache Kid
 * Kid Curry
 * Kid Poker
 * Willie Mays ("The Say Hey Kid")