Sherwood Schwartz: Television producer best known for the sitcoms ‘The Brady Bunch’ and ‘Gilligan’s Island’

The writer and producer Sherwood Schwartz had no reason to worry when two of his sitcom creations were panned by the critics: Gilligan's Island and The Brady Bunch were lapped up by viewers and went on to gain cult status. The first, which began in 1964, followed the two male crew and five passengers who were shipwrecked on a remote Pacific island after their charter boat, the SS Minnow, ran into a tropical storm during its three-hour tour. Schwartz described it as "my version of a social microcosm, where seven people from various backgrounds had to learn to live together".

Bob Denver starred as the bumbling crewman Gilligan, whose efforts to escape were usually thwarted by his own ineptness, and Alan Hale Jr played the long-suffering skipper, Jonas Grumby. The castaways used natural resources such as bamboo to make huts, tables and chairs but seemed unable to construct a raft that would carry them to freedom. Critics also scoffed at visitors arriving on the island and leaving without providing help.

But the world that Schwartz created won over viewers, who were lured into it each week with a theme song that he co-wrote himself with George Wyle, The Ballad of Gilligan's Isle, introducing the characters and their predicament. By the time the programme was axed in 1967 there had been no escape or rescue.

It retained enough interest to spawn two animated series, The New Adventures of Gilligan (1974-77) and Gilligan's Planet (1982-83), as well as three television films, Rescue from Gilligan's Island (1979), The Castaways on Gilligan's Island (1979) and The Harlem Globetrotters on Gilligan's Island (1981). Schwartz also devised a stage show, Gilligan's Island: The Musical, which has toured the US since 1992.

He had similar, long-running success with The Brady Bunch (1969-74), about two families becoming one after the marriage of Mike Brady (Robert Reed), a widowed architect with three sons, and Carol Martin (Florence Henderson), who had three daughters. Again, Schwartz wrote the theme song, which explained this "blending" – at a time when divorce and re-marriage were topical themes. (He conceived The Brady Bunch after reading a report that 40 per cent of marriages in the US involved children from previous marriages.) Although the sitcom never had sky-high viewing figures, it remained popular – particularly with children returning home from school – when it was repeated on cable channels.

Spin-offs have included the cartoon series The Brady Kids (1972-74),the television film The Brady Girls Get Married (1981), followed by one season of The Brady Brides (1981), another feature-length production, A Very Brady Christmas (1988), and the less successful series The Bradys (1990). Again, there was a stage production, The Real Live Brady Bunch, from 1991.

With the original remaining part of the American psyche, it was parodied in the 1995 film The Brady Bunch Movie, with the characters played by new actors, as well as A Very Brady Sequel (1996) and the television film The Brady Bunch in the White House (2002). All were produced by Schwartz but scripted by others.

Born in New Jersey in 1916, Schwartz attended DeWitt Clinton High School, New York, graduated from New York University and began a masters degree in biology at UCLA but abandoned it – and plans to become a doctor – when his brother Al was scripting sketches and routines for The Bob Hope Show on radio and he saw the chance to do the same himself. He was taken on as a staff writer (1939-42) after his brother showed the star some of his jokes, then worked on other radio programmes. During Second World War service in the US Army he wrote shows for the Armed Forces Radio Service.

Schwartz then switched to radio sitcoms, starting with The Adventures of Ozzie and Harriet, before moving to television to join the scriptwriting team for I Married Joan (1952-55). He was soon head writer (1954-62) on The Red Skelton Show but did not get along with the star – known for his bad relations with writers – and recalled in his 1988 book Inside Gilligan's Island that he had it written into his contract that they never had to meet face to face. With the rest of the programme's script team, he shared a 1961 Emmy award.

Schwartz was then script consultant (1963-64) for My Favorite Martian. His other television sitcom creations were It's About Time (1966-67, about two time-travelling astronauts) and Dusty's Trail (1973-74, transplanting Gilligan's Island's "lost group" idea to 19th century travellers separated from their wagon train).

Sherwood Charles Schwartz, writer and producer: born Passaic, New Jersey 14 November 1916; married 1941 Mildred Seidman (three sons, one daughter); died Los Angeles 12 July 2011.