Sometimes actors want to have a say in the words they're given; sometimes they want to stretch their artistic muscles; sometimes they look at the scripts they have to do and think, "I could do better than this!" When this happens, and the producers are on their side ([[ExecutiveMeddling or the network is]]), you have something written by a cast member.

Much less prevalent than DirectedByCastMember, particularly in these days of arc-driven television. Writing is less glamorous than directing, for one thing, and it's harder to develop a story from scratch than to bring someone else's to the screen.

Key to both of these tropes is that the actor gets into writing or directing through the show they're on, '''without''' having a previous background in it (let alone being the series creator). For the opposite direction of crossover, see DescendedCreator and CreatorCameo. For shows where the cast and the writing staff heavily overlap, see CastFullOfWriters.

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!!Examples:

[[foldercontrol]]

[[folder: Live-Action Film ]]

* Creator/ChristopherReeve was offered credited story input to entice him back for ''Film/SupermanIVTheQuestForPeace''. The title and anti-nuclear theme were his, and he won a lawsuit against a writing duo who claimed otherwise.
* Creator/MattDamon and Creator/BenAffleck both starred in and wrote GoodWillHunting.
* ''Film/TheDevilsHairpin'' was written and directed by Cornel Wilde who also is the main star.\\
Wilde also wrote a song called 'Swing It Just a Little More' for the soundtrack alongside [[WesternAnimation/TheAlvinShow Ross Bagdasarian]] who also wrote 'The Touch of Love' for the soundtrack as well.
* Creator/LeonardNimoy helped develop the [[Film/StarTrekIVTheVoyageHome fourth]] and [[Film/StarTrekVITheUndiscoveredCountry sixth]] ''Franchise/StarTrek'' films, and like Reeve, had the writers of an unused script try to muscle him out of the latter credit. (Coincidentally, they were the ''legitimate'' screenwriters of ''Superman IV''.) A lawyer-negotiated compromise saw Nimoy share story credit with the pair.
** ''Film/StarTrekVTheFinalFrontier'' was based on a story by Creator/WilliamShatner. His original outline was titled ''[[AccidentalInnuendo An Act of Love]].''
** Creator/BrentSpiner received co-story credit for ''Film/StarTrekNemesis''.

[[/folder]]

[[folder: Live-Action TV ]]

* ''Series/SmallWonder'' had a few episodes written, at least in part, by Dick Christie.
* Sonia Manzano has played Maria on ''Series/SesameStreet'' since 1971, and has written for the show since 1981.
* During their days on ''HeadOfTheClass'', Brian Robbins and Creator/DanSchneider had their first writing credits on the "Will The Real Arvid Engen Please Stand Up?" episode. [[TheAmandaShow And]] [[Series/AllThat the]] [[Series/KenanAndKel rest]] [[Series/ICarly is]] [[Series/{{Victorious}} history]].
* Brian Krause (Leo) is the only cast member of ''Series/{{Charmed}}'' to co-write an episode: he has co-story credit on "Sense And Sense Ability." [[ExecutiveMeddling He's said the finished product was different from what he turned in.]]
* Unlike DirectedByCastMember, very few episodes of the ''Franchise/StarTrek'' franchise qualify - in fact, the only ones are ''[[Series/StarTrekDeepSpaceNine DS9]]'s'' "The Muse" (co-written by Majel Barrett-Roddenberry) and ''[[Series/StarTrekVoyager Voyager]]'s'' "Life Line" (co-written by Robert Picardo). Both focused on those actors' characters. (Creator/WalterKoenig wrote "The Infinite Vulcan" for [[WesternAnimation/StarTrekTheAnimatedSeries the animated series]], but due to budget limitations, ''wasn't'' a cast member on that show.)
* Barry Watson wrote an episode of ''Series/SeventhHeaven'' (not one of the two he directed).
* Robert Culp loved doing this on his shows: ''Trackdown'', ''Series/ISpy'', and ''TheGreatestAmericanHero'' all had episodes he wrote (AND directed). In addition, he wrote one of the two episodes of ''Cain's Hundred'' on which he guest-starred (strangely averted with ''The Rifleman'' - he guest-starred on two episodes and also wrote a two-parter in which he does ''not'' appear!).
* John Schneider co-wrote and directed "Opening Night At The Boar's Nest," the SeriesFinale of ''Series/TheDukesOfHazzard''.
* In addition to being the only person to apppear in every episode of ''Series/{{MASH}}'', Alan Alda also wrote numerous episodes (and was one of the writers of the SeriesFinale to boot).
* Both Dean Cain and Creator/TeriHatcher wrote episodes of ''[[Series/LoisAndClark Lois and Clark: The New Adventures of Superman]]''.
* Jack Klugman, who made no secret of his views on the standard of writing in TV, wrote or co-wrote four episodes of ''Series/{{Quincy}}'' in addition to [[CreativeDifferences having showrunner Glen A. Larson thrown off the show]] and eventually getting writers more to his liking. [[{{Nepotism}} Including his own brother and sister]].
* Don Adams co-wrote two episodes of ''Series/GetSmart''.
* Peter Falk wrote one script for ''Series/{{Columbo}}'', in which the Lieutenant is romanced by a FemmeFatale. He held it back until finding the perfect co-star: Faye Dunaway, who turned the role into an Emmy.
* Roger Smith wrote several episodes of ''77 Sunset Strip''.
* Done quite a bit on ''Series/TheXFiles'', especially in later seasons. Creator/DavidDuchovny wrote (and directed) two episodes: "The Unnatural" and "Hollywood AD", while co-developing storylines for seven others. Gillian Anderson wrote (and directed) season seven's "all things." William B. Davis (who plays CGB Spender) wrote "En Ami."
* Two episodes of ''Series/WizardsOfWaverlyPlace'' were written by DavidHenrie.
* Two episodes of ''Series/{{Farscape}}'' (Season 3's "Green-Eyed Monster" and Season 4's "John Quixote") were written by Ben Browder.
* Christopher Judge (Teal'c) and Michael Shanks (Daniel Jackson) wrote multiple episodes of ''Series/StargateSG1''.
* Nick Offerman earned his first writing credit for a ''Series/ParksAndRecreation'' script.
* Michael Imperioli wrote several episodes of ''Series/TheSopranos''. This is [[ActorAllusion reflected]] in Christopher Moltisanti's interest in film and screenwriting.
* Michael Landon got his start in writing with several scripts for his hit series ''Series/{{Bonanza}}''. He went on to write more episodes of ''Series/LittleHouseOnThePrairie'' than anyone else, as well as create another successful vehicle for himself in ''Series/HighwayToHeaven''.
* A handful of ''Series/MightyMorphinPowerRangers'' episodes were written by Paul Schrier, who played Bulk.
** And [[Series/PowerRangersJungleFury Jason Smith]] wrote a few episodes of ''[[Series/PowerRangersMegaforce Power Rangers Super Megaforce]]'', though oddly not the episode where he reprises his ''Jungle Fury'' role as Casey, that season's red ranger.
* Patrick Labyorteaux (Bud) wrote the episode "JAG TV" on ''Series/{{JAG}}''.
* Several ''Series/{{CSI NY}}'' cast members have tried their hand at writing an episode. Gary Sinise has done one or two, and Melina Kanakaredes did an ep where Stella goes to Greece chasing a suspect-an ep which unfortunately drew mixed reviews from fans.
* David Faustino (Bud) co-wrote one episode of ''Series/MarriedWithChildren''.
* James Roday has written or co-written over a dozen episodes of ''Series/{{Psych}}'', one of which was an elaborate homage to ''Series/TwinPeaks'' (his "favorite show of all time, hands down.")
** In one of the HilariousOuttakes, when James messes up on his lines, his co-star jokes that he should remember the lines since he's the one who wrote them
* ''Series/StElsewhere'': Sagan Lewis (Dr. Jackie Wade) is credited for the story of Season 6's "Their Town" as S.J. Lewis.
* Creator/ChadMichaelMurray wrote an episode of ''Series/OneTreeHill'' in which Lucas falls asleep watching ''Film/{{Casablanca}}'' and dreams the show's cast into a [[TheForties Forties]] FilmNoir world.
* Creator/EllenDeGeneres is credited for the story of ''Series/{{Ellen}}'''s [[ComingOutStory coming out episode]].
* Jerry O'Connell and JohnRhysDavies each received a story credit on ''Series/{{Sliders}}'' - O'Connell got a few such credits (such as on "Way Out West") while Rhys-Davies only got it for "The Exodus, Part 1." In the latter case, it was the culmination of [[CreativeDifferences his feud with the producers and network]]: they purchased an outline he pitched as an example of how the show could better use its potential, drastically rewrote it into the kind of embarrassing B-movie he'd been complaining about, and [[spoiler:since he had just been fired for his outspokenness, [[McLeaned reduced his character to a mumbling brain-damaged state, fatally shot him in the heart, and left his corpse behind on a radioactive planet.]] ''[[ThereIsNoKillLikeOverkill Which immediately exploded.]]'']]
* Yaphet Kotto wrote three teleplays for ''Series/HomicideLifeOnTheStreet''.
* Paul Gross wrote or co-wrote some of the most memorable episodes of ''Series/DueSouth'', including the introduction of Kowalski and the two-part series finale.
* Della Reese contributed a script to ''Series/TouchedByAnAngel''.
* Ray Romano co-wrote several episodes of ''Series/EverybodyLovesRaymond'', including some {{Whole Episode Flashback}}s filling in Raymond's past.
* Ted Raimi and Jonathan Brandis each wrote an episode of ''Series/SeaQuestDSV'' with the help of producer David J. Burke. Brandis was set to direct a second script he had written when the series was CutShort.
* Denise Nicholas wrote six episodes of ''Series/InTheHeatOfTheNight''.
* As well as directing the first season finale of ''The Client List'', JenniferLoveHewitt has co-story credit on that episode.
* Stuart Hepburn played a recurrent character in early episodes of {{Taggart}}. The producer was so impressed by ideas he had for one scene he was in that he was later invited to come back and write whole episodes; he quickly became one of the most prolific writers after series creator Glenn Chandler.
* Jim Rash wrote "Basic Human Anatomy" for the fourth season of ''{{Community}}''.
* ''Series/{{Glee}}'''s Chris Colfer wrote season five's "Old Dog, New Tricks."
* Outside of three cast members of ''TheOfficeUS'' being staff writers (B.J. Novak, Mindy Kaling, and Paul Lieberstein), SteveCarell also wrote the season 2 finale "Casino Night" as well as "Survivor Man".
* Creator/SaraGilbert received a story credit on Series/{{Roseanne}} for the Season Episode "Don't Make Me Over."

[[/folder]]

[[folder: Radio ]]

* In 1955, ''Radio/TheArchers'' had an episode where Grace Archer, the wife of Phil, was killed off. (It may or may not have been coincidence that the episode went out on BBC radio the very night [[{{ITV}} commercial television]] began.) The script had Grace's fate be conveyed in the final line of dialogue thusly: "She... she died in my arms... on the way to hospital," but Norman Painting, who played Phil, suggested the line go "In my arms... on the way to hospital... she's dead!" Suffice to say that not only was this one of the most talked-about episodes of the soap, but Painting went on to write many, many episodes (and the book ''Forever Ambridge 25 Years of The Archers''), as well as act in them.

[[/folder]]

[[folder: Theatre ]]

* In ''Theatre/{{Godspell}}'', "By My Side," the only song retained from the original Off-Off-Broadway production, was composed by its performers, Peggy Gordon and Gilmer [=McCormick=] (with lyrics by non-cast-member Jay Hamburger).

[[/folder]]

[[folder: Western Animation ]]

* Creator/DanCastellaneta has so far written seven episodes of ''WesternAnimation/TheSimpsons'' with [[CreatorCouple his wife]] Deb Lacusta ("Days Of Wine And D'oh'ses"[[note]]season 11 episode where Barney gives up drinking and Bart and Lisa try and look for the perfect photograph for the town's phone book contest[[/note]], "Gump Roast"[[note]]the final clip show episode from season 13 where Homer is honored at the Friars' Club with a roast[[/note]], "The Ziff Who Came To Dinner,"[[note]]season fifteen episode where Artie Ziff hides out at the Simpson house after his business goes under and he's being hounded for cheating his shareholders[[/note]] "Kiss Kiss Bang Bangalore,"[[note]]season seventeen episode where Homer goes to India after Mr. Burns outsources the nuclear plant while Patty and Selma kidnap Richard Dean Anderson after he tells them that he only did ''{{MacGyver}}'' to earn a paycheck[[/note]] "The Fight Before Christmas,"[[note]]a bizarre ChristmasEpisode that had an ''Inglorious Basterds'' parody, Martha Stewart showing Marge the true meaning of Christmas, and KatyPerry as the only human in a piece that has The Simpsons as Muppets[[/note]] "A Midsummer's Nice Dream,"[[note]]the episode where stoner comedians Cheech and Chong break up and use Homer and Principal Skinner as their new comedy partners while Marge tries to help the Crazy Cat Lady with her hoarding problem[[/note]] and "The Ten-Per-Cent Solution"[[note]]the episode where Krusty's show gets canceled again and Joan Rivers voices his first agent, who helps him revive his career with a cable show[[/note]]).
** He also co-wrote at least one sketch of ''The Tracey Ullman Show''.
* Jack Mercer not only voiced ComicStrip/{{Popeye}} but wrote several of his screen exploits.
* Creator/WillFriedle has written two episodes of ''WesternAnimation/ThunderCats2011'': "The Trials of Lion-O - Part 2" and "Birth of the Blades". Both focus on Friedle's character, Lion-O.
* Voice actor Creator/BillyWest received co-author credit on the ''WesternAnimation/TheRenAndStimpyShow'' episode "Ol' Blue Nose".
* April Winchell, the voice of Miss Finster, also did some punch-up writing for ''WesternAnimation/RecessSchoolsOut''
* On ''MickeysChristmasCarol'', Alan Young, the voice of Scrooge, receives a story credit.
* Some episodes of ''WesternAnimation/{{Spliced}}'' were written by Mike Kiss, who also voices Mister Smarty Smarts.
* The ''WesternAnimation/TinyToonAdventures'' episode "Best of Buster Day" was co-written by Creator/CharlieAdler, who voices Buster.
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