Surprised nobody has mentioned Trailer Park Boys.
Or British shows which meets the OP.
British Sitcom Man About The House (1973) ran for 6 seasons (series in the UK) and then had a spin off film realised theatrically in the UK. The film made by Hammer better known for their horror films.
There were also two spin off Sitcoms: George and Mildred (1976) which ran for five seasons and had a spin off film. There would have been a sixth season but the female star - Yootha Joyce - died. The other spin off was Robin’s Nest (1977) which ran for six seasons but that one failed to get a film.
Still with British shows and comedy On The Buses (remade in America as Lotsa Luck) made seven seasons from 1969 and had three films - made by Hammer.
I believe 1972 sitcom Are You Being Served? is known in America. That made ten seasons and had a spin off film. Plus a 1992 spin off sitcom Grace and Favour lasted two seasons.
Sitcom Steptoe and Son (remade in the UK as Sanford and Son) reached eight seasons and two films.
British cop show The Sweeney (1975) doesn’t count because they only made four seasons but they were fine television and they did manage two films and much later, 2012, there was a remake film featuring Ray Winstone who was not a star in the original TV show although he did appear as a minor villain.
Popular WW2 sitcom Dad’s Army originally ran for nine seasons from 1968 and had a film during that time. However a remake film is now in production and starring Bill Nighy and Catherine Zeta Jones a theatrical release seems likely for 2016.
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Honorable mention to THE LONE RANGER: Clayton Moore played the masked man on the big screen in THE LONE RANGER AND THE LOST CITY OF GOLD after the show ran for hundreds of episodes from 1949 to 1957 – which only count as five seasons.
Reno 911! made (exactly) six seasons and a movie.
And Beavis & Butthead
Another British series, although maybe not quite a fit: The Avengers, six series (with cast changes), and a US-produced theatrical film with Ralph Fiennes and Uma Thurman.
Another variation in the OP. The mainstay of British cinema from the late 1950s into the Late 1970s (then a final, feebler than most entry in the 1990s) were the 31 Carry On films. As their cinematic pulling power waned the producers tried switching to the small screen and made two series of Carry On Laughing TV shows in the late 1970s.
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The Life and Legend of Wyatt Earp, with Hugh O’Brien, went six seasons from 1955 to 1961. The most notable film was Tombstone in 1993, followed by Wyatt Earp the following year.
I’m not sure that counts, as I think those movies are based on the life of Wyatt Earp and not necessarily based on the series.
Hmm. McHale’s Navy only had 4 seasons, but it had two\ movies with the original cast, plus one in 1997 with Tom Arnold. Doesn’t quite make it
But The Beverly Hillbillies ran nine seasons, and had one theatrical film (without the original cast), along with a few TV movies (with them).
Dragnet ran for 8 seasons initially,three later, and one later still. There was a theatrical film with the original cast b(and in COLOR!) in 1954, along with a later TV movie/pilot and the Dan Ackroyd/Tom Hanks comedy (which had Morgan from the csecond series).
Man from U.N.C.L.E. only had four seasons, but it spawned two little-known movies with the original casts (in fact, they were “expanded” episodes of the TV series, with added subplots, sex, and violence). Six others were released overseas.
And that’s in addition to the current non-OC movie.
Part of the reason for the theatrical release, interestingly, is that they were in COLOR, when most people still only had black and white TVs.
The Powerpuff Girls - 6 seasons, 1 movie, revival series on the way
Aqua Teen Hunger Forice - 11 seasons, 1 movie (and associated ridiculous bomb scare in Boston)
Adventure Time - 6 seasons so far, renewed for 2 more, movie announced for 2016.
Okay, I quit.
I realize that TV movies “don’t count”, but it should be pointed out that Gunsmoke had a 20 year run on TV (and a 9 year run on radio), and there were three TV movies from 1987-1994 (the TV series ended in 1975), using at least some of the original cast.
There never was a non-TV film. Nor one of Bonanza, which also had a long run (although it spawned a series of later TV movies, too).
If we’re counting cartoon series (as suggested above), then The Flintstones qualifies. It ran six seasons of TV (not counting sequels, spinoffs and specials), and lead to the theatrical movie The Man Called Flintstone in 1966.
(And, of course, the much later non-cartoon, non-OC movies later)
The Flintstones - six seasons plus an animated film (The Man Called Flintstone) released in theaters (in addition to the live-action versions years later).
Rugrats - nine seasons and three movies
Also, depending on what you consider a “season”, Recess had six seasons and a movie (Recess: School’s Out), along with a spinoff/sequel series. The problem is, the show’s last two seasons had nine and five episodes, respectively; when what were supposed to be the last three episodes became the movie instead, three new episodes were made for overseas sales, and ABC aired one or two per year so it could claim, “We have new episodes this year!” Similar “creative counting” could be used for Hey Arnold!, which had five full seasons, a movie, and two specials that aired after the movie. Note that, outside of the USA, both are usually counted as five 20-episode seasons.
Mentioned in post #16.
Sorry – didn’t notice that until afterwards.
But it’s one of the things that occurred to me as soon as I saw the thread title.
Several series just fell short of the mark: The A-Team, Charlie’s Angels, Maverick, and 21 Jump Street only made it to five seasons and a movie. Starsky & Hutch and The Wild Wild West only made it to four seasons and a movie.
Dark Shadows reached six seasons and a movie.