In short, the executive producer who serves as the head writer. The longer answer is that the showrunner is the person who gives the show its tone and direction.

The initial showrunner is usually the creator (frequently the writer of the {{pilot}}). As the years pass, the original showrunner may leave and a new one may join - this can often be a JumpTheShark or GrowingTheBeard moment.

Not to be confused with someone like a go-fer or someone who goes and get things for others - this person ''runs the show''.

!! Creator/Showrunners:
* Danny Arnold: ''Series/BarneyMiller''
* Creator/DonaldPBellisario:
** ''Series/MagnumPI'' (co-creator with Glen A. Larson, who had nothing to do with the show after the pilot)
** ''TalesOfTheGoldMonkey''
** ''Series/{{Airwolf}}''
** ''Series/QuantumLeap''
** ''Series/{{JAG}}''
** ''Series/{{NCIS}}'' (co-creator with Don [=McGill=])
* Rick Berman and Brannon Braga: ''Series/StarTrekEnterprise'' (Seasons 1-3)
* Creator/StevenBochco: ''Series/HillStreetBlues'', ''Series/LALaw'', ''Series/NYPDBlue''
* Creator/StephenJCannell: ''Series/TheRockfordFiles'', ''Series/TheATeam'', ''Series/TheGreatestAmericanHero'' (and most of his other series, in fact)
* David Chase: ''Series/TheSopranos''.
* Marc Cherry: ''Series/DesperateHousewives''
* David Greenwalt: ''{{Angel}}'' (Seasons 1-3. Co-creator with Creator/JossWhedon, who remained on as writer and executive producer throughout all five seasons, but never became showrunner, even after Greenwalt left to work on ''Miracles''.)
* David X. Cohen: ''WesternAnimation/{{Futurama}}'', (Co-creator with Creator/MattGroening)
* Marta Kauffman & David Crane: ''Series/DreamOn'', ''The Powers That Be'', ''Series/{{Friends}}'' (Seasons 1-3, though they remained involved as producers and occasional writers throughout the rest of the series.), ''Veronica's Closet''.
* Creator/LarryDavid (seasons 1-7), and Jerry Seinfeld (seasons 8 & 9): ''Series/{{Seinfeld}}'' (Larry David was the sole showrunner throughout most of it's run. When David left after season 7, co-creator and star Jerry Seinfeld became the showrunner for the last two seasons.)
* Creator/TinaFey: ''Series/ThirtyRock''. Also plays a showrunner on the show.
* Creator/BryanFuller: ''PushingDaisies''
* Larry Gelbart (seasons 1-4): ''Series/{{MASH}}''
* Matt Groening, James L. Brooks & Sam Simon: ''WesternAnimation/TheSimpsons'' (season 1 and 2)
* Dan Harmon: ''Series/{{Community}}'' (seasons 1-3; reinstated in season 5)
* Buck Henry: ''Series/GetSmart''. (co-creator Mel Brooks had little involvement with the series after the pilot)
* Mitchell Hurwitz: ''Series/ArrestedDevelopment''
* David E. Kelly: ''AllyMcBeal'', ''ThePractice'', ''BostonLegal''
* Creator/BryanKonietzko and Creator/MichaelDanteDiMartino: ''WesternAnimation/AvatarTheLastAirbender'' and its SequelSeries ''WesternAnimation/TheLegendOfKorra''.
* Creator/EricKripke: ''Series/{{Supernatural}}'' (seasons 1-5), ''Series/{{Revolution}}''
* Creator/NormanLear: ''Series/AllInTheFamily'', ''Series/{{Maude}}'', ''Series/SanfordAndSon''.
* Howard Leeds: ''SmallWonder''
* Ryan Murphy: Brad Falchuk and Ian Brennan [[FanNickname (collectively known as RIB)]]: ''{{Glee}}''
* Shonda Rhimes: ''GreysAnatomy'' and ''PrivatePractice''.
* GeneRoddenberry:
** ''The Lieutenant'' (1963-64)
** ''Series/StarTrekTheOriginalSeries'' (for the first several episodes of season 1, along with "The Menagerie" and "[[PoorlyDisguisedPilot Assignment: Earth]]")
** ''Series/StarTrekTheNextGeneration'' (season 1 only)
* Shawn Ryan: ''TheShield''
* Creator/DanSchneider: ''Series/ICarly'', ''DrakeAndJosh'', and ''{{Victorious}}''
* Amy Sherman-Palladino: ''GilmoreGirls'' (seasons 1-6)
* Paul Simms: ''NewsRadio''
* Creator/DavidSimon: ''TheWire'' and ''The Corner'' (He also wrote the book on which ''HomicideLifeOnTheStreet'' was based, and later joined the writing staff.)
* Creator/AaronSorkin: ''SportsNight'', ''Series/TheWestWing'' (Seasons 1-4), ''Studio60OnTheSunsetStrip'', ''TheNewsroom''
* J. Michael Straczynski: ''Series/BabylonFive''
* Kurt Sutter: ''SonsOfAnarchy''
* Jeri Taylor: ''Series/StarTrekVoyager'' (jointly with co-creator Michael Piller for seasons 1-2; left after season 4)
* Heidi Thomas: ''Series/CallTheMidwife''
* Matthew Weiner: ''MadMen''
* Creator/DickWolf: ''Series/LawAndOrder''
* Creator/JossWhedon: ''Series/BuffyTheVampireSlayer'' (except for season 6) and ''Series/{{Dollhouse}}''
* Bruno Heller: ''TheMentalist'', ''Series/{{Rome}}''.
* Vince Gilligan: ''Series/BreakingBad''.
* Jeff Marsh and Dan Povenmire: ''PhineasAndFerb''.
* Glen and Les Charles: ''Series/{{Cheers}}'' for Seasons 1-2. (co-created with James Burrows, who was a director and not involved with the actual writing process)
* Nell Scovell: ''Series/SabrinaTheTeenageWitch'' (season 1 only)
* Greg Daniels: ''Series/KingOfTheHill'' - Seasons 1 & 2 (co-created with Mike Judge), ''Series/TheOfficeUS'' (Seasons 1-4 & 9)
* Alfred Gough & Miles Millar: ''The Strip'', ''Series/{{Smallville}}'' (seasons 1-7), [[Series/CharliesAngels Charlie's Angels 2011 revival series]]
* Carter Bays & Craig Thomas: ''Series/HowIMetYourMother''
* David Crane & Jeffery Klarik: Series/TheClass, ''Series/{{Episodes}}''.
* Jed Whedon & Maurissa Tancharoen: ''Series/AgentsOfSHIELD'' (co-created with Joss Whedon)

!! Showrunnners Who Took Over Existing Shows
* Creator/RussellTDavies: ''Series/DoctorWho'' - Series 1-4 + 2009 Specials.
* Creator/StevenMoffat: ''Series/DoctorWho'' - Series 5 onwards.
* Al Jean & Mike Reiss: ''TheSimpsons'' - Seasons 3 & 4
** David Mirkin: Seasons 5 & 6
** Bill Oakley & Josh Weinstein: Seasons 7 & 8.
** Mike Scully: Seasons 9 through 12.
** Al Jean: Season 13 to present.
* Gene L. Coon assumed the role of showrunner from Gene Roddenberry after the initial batch of episodes from the first season of ''Series/StarTrekTheOriginalSeries'', starting with "Miri", and he continued in this role until halfway through season 2 ("Bread and Circuses" was his last episode as Producer). He actively produced nearly half of the show's 79 episodes, more than anyone else. He was replaced for the rest of the second season by writer/director John Meredyth Lucas, who left only because Gene Roddenberry was supposed to come back the following season, though he ultimately did not. Notably, both Coon - under the pseudonym "Lee Cronin" - and Lucas continued to write (and in the latter's case, direct) for the show even after having stepped down as showrunner. Journeyman producer Fred Freiberger became showrunner for the third season (often referred to as the [[SeasonalRot turd season]]), and became the [[MisBlamed scapegoat]] for all its problems.
* Ira Steven Behr took over ''Series/StarTrekDeepSpaceNine'' from Season 3 onwards, leading to much [[GrowingTheBeard facial hair growth]].
* Maurice Hurley became showrunner in the second seasons of ''Series/StarTrekTheNextGeneration'' and ''{{Baywatch}} Nights''. His work on the former helped the show move towards fully GrowingTheBeard, but his efforts on the latter proved that no matter how badly a show starts out, it can still JumpTheShark spectacularly.
* Michael Piller became the showrunner for the third season of ''Series/StarTrekTheNextGeneration'', and held the role for the rest of its run. He also acted as showrunner for the first two seasons of ''Series/StarTrekDeepSpaceNine'', and then joint showrunner (with Jeri Taylor) of the first two seasons of ''Series/StarTrekVoyager''.
* Brannon Braga became the showrunner of ''Series/StarTrekVoyager'' for seasons 5-6, departing in season 7 to develop ''Series/StarTrekEnterprise''. Like Freiberger before him, he became a major scapegoat, and is often blamed for ''all'' of the problems with the show's creative direction throughout its entire run.
* Kenneth Biller became the final showrunner for ''Series/StarTrekVoyager'' in season 7.
* Manny Coto took over primary showrunning duties from Rick Berman and Brannon Braga in the fourth season of ''Series/StarTrekEnterprise'', replacing Braga as executive producer. Although season 4 was generally considered the best one, it was too late to save the show from cancellation.
* Writer/Actor Paul Lieberstein, for seasons 5-8 of ''Series/TheOfficeUS''.
* Writer/executive producer Sera Gamble worked as showrunner for ''Series/{{Supernatural}}'' on Seasons 6 and 7.
** Jeremy Carver took over from Gamble starting with Season 8.
* Neal Baer became showrunner of ''LawAndOrderSpecialVictimsUnit'' for season 2, replacing original showrunner Robert Palm, and has remained in that position for ''eleven seasons'', the longest tenure in franchise history. He will be moving on at the end of season 12.
* Rene Balcer assumed the role of showrunner for the original ''LawAndOrder'' twice: once in the late '90s, and again in the late noughties. In both cases, he left to helm a spinoff as the initial showrunner: First ''LawAndOrderCriminalIntent'', and then ''Law & Order: Los Angeles''.
* When Marti Noxon was promoted to executive producer for Season 6 of ''Series/BuffyTheVampireSlayer'', she also became showrunner for that season, since JossWhedon was initially preoccupied with the creation of a single episode ("Once More With Feeling"), as well as prepping ''Series/{{Firefly}}''.
* After David Greenwalt left ''Series/{{Angel}}'', Jeffrey Bell took over as showrunner for the final two seasons. [[note]]David Simkins, best known as a writer and producer on ''Series/{{Charmed}}'', was brought in as showrunner for Season 4, but left due to creative differences after four episodes and was entirely uncredited; Bell replaced him and remained for the duration of the show.[[/note]] It is speculated that he will also act as showrunner on Joss Whedon's new ''Agents of S.H.I.E.L.D.'' show, since he's the only one of the other four listed executive producers to have showrunning experience.
* Following the Charles Brothers stepping out of the showrunners' positions on ''Series/{{Cheers}}'', they were followed by:
** Season 3: Ken Estin
** Seasons 4-7: David Angell, Peter Casey and David Lee
** Seasons 8-10: Cheri Eichen, Bill Steinkellner and Phoef Sutton
** Season 11: Dan O'Shannon and Tom Anderson
* Gene Reynolds (season 5), and Burt Metcalfe (seasons 6-11): ''Series/{{MASH}}'' (Creator Larry Gelbart and Gene Reynolds were the co-producers of the show for the first four seasons; when Gelbart departed after season 4, Reynolds took over for the fifth season, and after he too departed, Burt Metcalfe took over after previously being the show's associate producer up till then).
* When ''Series/{{Friends}}'' creators Marta Kauffman and David Crane stepped down as showrunners to work on their new show ''Veronica's Closet'', they were followed by:
** Season 4: Michael Borkow
** Seasons 5 & 6: Adam Chase
** Season 7: Wil Calhoun
** Seasons 8-10: Shana Goldberg Meehan & Scott silveri
* When ''Series/SabrinaTheTeenageWitch'' creator Nell Scovell stepped down after season 1, the showrunners were:
** Seasons 2-4: Miriam Trogdon
** Seasons 5 & 6: Bruce Ferber
** Season 7: David Babcock
* While ''Series/KingOfTheHill'' co-creator Greg Daniels remained a large creative force through the end of season 4, the main showrunners after season 2 were:
** Seasons 3-5: Richard Appel
** Season 6: Jonathan Aibel & Glenn Berger
** Seasons 7-13: John Altschuler & David Krinsky
* When Creator/AaronSorkin left ''Series/TheWestWing'' at the end of season 4, veteran ''Series/{{ER}}'' producer John Wells became the showrunner of the last three seasons.
* When ''Series/{{Smallville}}'' creators Alfred Gough and Miles Millar left at the end of season 7, Todd Slavkin, Darren Swimmer, Kelly Sounders, and Brian Peterson became the showrunners of the eighth season. When Slavkin and Swimmer left at the end of season 8 to develop the [[Series/MelrosePlace Melrose Place 2009 revival series]], Sounders and Peterson became the sole showrunners for the last two seasons.

!! Shows Where the First Showrunner Was Not the Creator
* ''Series/{{Lost}}'' is a hybrid as far as the creator/showrunner classification is concerned. Created/showrun by J.J. Abrams and Damon Lindelof (Jeffrey Lieber, who shares "created by" credit, had nothing to do with the show after writing the original pilot script) and run since early on by Lindelof and Carlton Cuse.
* ''Series/DoctorWho'', which has only had a 'showrunner' position since the 2005 revival. Created primarily by Creator/SydneyNewman, Creator/VerityLambert, Donald Wilson and C. E. Webber. The original series may be said to have divided the showrunner's duties between the producer and the script editor; sometimes the former (eg. Creator/JohnNathanTurner from 1980 to the cancellation) or the latter (eg. Creator/DouglasAdams, 1979; Andrew Cartmel, 1987-89) seemed to have more of the role.
** Likewise, ''Series/{{Torchwood}}'' and ''Series/TheSarahJaneAdventures'' were both technically created by Creator/RussellTDavies, but the initial showrunners were Chris Chibnall and Phil Ford respectively. Davies later took full control of ''Torchwood'' starting with its third series (though apparently handed a lot of his duties over to Jane Espenson for ''Series/TorchwoodMiracleDay''), while Ford remained showrunner on ''The Sarah Jane Adventures'' for its entire run.
** AudioPlay/BigFinishDoctorWho, the audio series, had Gary Russell as its showrunner until 2009, when Creator/NicholasBriggs (the voice of the Daleks) took over the role.
* An odd example in ''WizardsOfWaverlyPlace'': The show's creator, Todd J. Greenwald, remains on-staff as a writer and producer, but he is ''not'' the showrunner - that honour went to Peter Murrieta for the first three seasons. (In the fourth season, he left and Greenwald stayed on - but Greenwald still did not become the showrunner.)
* Edward Allen Bernero wasn't the creator of Series/CriminalMinds, but was its showrunner from the pilot to the end of the sixth season.
* If a film series can count, producer David Heyman is essentially the showrunner of the ''Film/HarryPotter'' movie franchise. Directors come and go and Heyman is often the one who selects them.
* "Showrunning" duties on ''WesternAnimation/StarTrekTheAnimatedSeries'' were divided between story editor D.C. Fontana and animation director Hal Sutherland; Gene Roddenberry, despite receiving creator credit, had no involvement with the series (though he was listed as the "Executive Consultant", in a harbinger of [[Film/StarTrekIITheWrathOfKhan things to come]]).
* Tim Minear ran Joss Whedon's ''{{Firefly}}''.
* ''Series/{{Wings}}'' was created by the trio of David Angell, Peter Casey and David Lee, with the showrunners being:
** Seasons 1 & 2: Philip [=LaZebnik=]
** Seasons 3 & 4: Chris Lloyd
** Season 5: David Hackel
** Seasons 6-8: Ian Gurvitz
* ''Series/{{Frasier}}'' was also created by Angell, Casey and Lee, but Chris Lloyd was the showrunner in seasons 1-7 , Dan O'Shannon was the showrunner in seasons 8-10, while Lloyd retuned in season 11, this time co-running with Joe Keenan. Lee was the most involved out of the creator trio, frequently directing episodes of the show, while Casey and (until his death during 9/11) Angell's role was mostly limited to consulting on storylines.
* ''Series/{{ER}}'' was created by well known science fiction Author/Screenwriter Michael Crichton, the showrunners were:
** Seasons 1-3: John Wells (though he remained on as a producer and writer)
** Seasons 4-6: Lydia Woodward
** Seasons 7-9: Jack Orman
** Seasons 10-15: David Zabel
* While ''Series/{{Charmed}}'' was created by Constance M. Burge, Brad Kern was showrunner throughout all eight seasons. However, Burge remained on as writer and executive producer throughout the first two seasons before leaving at the end of season 2 due to creative differences with Kern.
* Showtime's ''Series/{{Dexter}}'' was created by James Manos Jr., the showrunners were:
** Seasons 1-4: Clyde Phillips
** Season 5: Chip Johannessen
** Seasons 6-8: Scott Buck

!! Showrunners in Fiction
* ''Series/ThirtyRock'': Liz Lemon is the showrunner for ''TGS with Tracy Jordan''--and is played by the aforementioned Tina Fey, the actual creator-showrunner for ''30 Rock''.
* ''Studio60OnTheSunsetStrip'': Matt Albie and Danny Tripp
* ''Almost Perfect'': Kim Cooper
* ''The TV Set'': Creator/DavidDuchovny plays beleaguered showrunner Mike Klein.

!! Long-Running Shows That Never Changed Showrunners
* ''CurbYourEnthusiasm'': Seven seasons, showrunner Creator/LarryDavid. The main character? [[AsHimself Larry David, a showrunner]].
----