Sherwood Schwartz began his professional writing career in radio in 1939. working for The Pepsodent Show Starring Bob Hope, where his older brother Al was also a writer. During World War II, Schwartz served with the Armed Forces Radio Service, writing for a variety of programs. Following the war, he re­turned to California and radio, writing for The Adventures of Ozzie and Harriet and The Beulah Show. During the 1950s, when many radio performers and programs migrated to television. Schwartz joined the move, working on I Married Joan and The Red Skel­ton Show. His work on the latter was recognized annu­ally by the Writer's Guild from 1955 to 1960 and included the only writing award ever given for pan­tomime, for "Freddie's Thanksgiving," in which not a single word was spoken. The guild again recognized his work in 1963-64 for the Lucille Ball Comedy Hour. Schwartz was also honored by the National Academy of Television Arts and Sciences. Nominated for Emmy Awards in 1961 and 1962 for Outstanding Writing Achievement in Comedy, he received the award in 1961.

In the early 1960s, in addition to writing for Skelton, Schwartz also worked on the first season of My Fa­vorite Martian. It was during this time that he devel­oped and pitched the concept for Gilligan's Island, his first foray as a series creator/producer. The Columbia Broadcasting System (CBS) was interested, and the se­ries became a joint production of CBS. United Artists, and Phil Silvers's Gladasya Productions. The pilot was shot in Hawaii in November 1963 (and interrupted by the assassination of President Kennedy), but three dif­ferent versions were rejected by CBS. Having dis­avowed himself from the original cut of the pilot, Schwartz persisted and received permission (but no funding) from United Artists to use the footage and re­ cut the pilot yet a fourth time. This was the only ver­sion to include the opening theme, for which Schwartz wrote the lyrics. In 60 seconds, the song provided ex­position-which Schwartz had argued all along was crucial to the program-to explain why the castaways remained on the island week after week. This version of the pilot was delivered to CBS the Friday  before the network was to announce its fall 1964 schedule; CBS executives were sufficiently impressed with Schwartz's version to run audience tests over the weekend. and as a result of those tests, Gilligan’s lsland was added to the CBS schedule . In each of the next three seasons the program aired in a different time period and on a different night, but it always won its time slot and was often in the top ten of the national Nielsen ratings. Although renewed for a fourth season, Gilligan’s Island was later dropped to make room for Gunsmoke, which had originally been cut from CBS's 1967-68 schedule . Since the end of its prime-time net­ work run. Gilligan's Island has been one of the most successful programs in the history of television syndi­cation. Constantly in reruns, it was first a staple on lo­ cal broadcast stations as after-school fare for children and later on cable channels. The show spawned two animated series (The New Adventures of Gilligan, American Broadcasting Company [ABC], 1974-77 and Gilligan’s Planet, ABC. 1982-83) and three tele­ vision movies.

Schwartz's second major series contribution to tele­vision came two years after Gilligan. With an idea springing in part from an article he read in 1966, indi­cating that more than 20 percent of all marriages in­cluded children from a previous marriage, he created The Brady Bunch. Once again Schwartz wrote the theme song lyrics, this time for the story of "a lovely lady" and "a man named Brady" and their two sets of kids. He pitched the program to all three networks, and it was rejected. Following the box office success of the Henry Fonda/Lucille Ball film Yours, Mine and Ours in 1968, however, (a film developed after Schwartz created his TV concept), the show became part of ABC's 1969 fall schedule. The program was not a huge ratings success, generally falling in the 20 to 30 range in the national Nielsen ratings. but it did attract the young viewers ABC was seeking.

While Schwartz's programs were dismissed as typi­cal lowbrow television, recent critical views have cast his work in a more favorable light. At a time when the family was the basis for the typical TV sitcom, Gilli­gan’s Island offered a different sort of family (Schwartz called it a "social microcosm" in his pitch to CBS) years before the celebrated ensemble/workplace sitcoms of the 1970s, such as M*A*S*H and The Mary Tyler Moore Show. Schwartz also pioneered the sitcom reunion movie concept, used to great success with both Gilligan’s Island (three movies) and The Brady Bunch. The characters/series concept of the latter proved to be very resilient, extended to a range of follow-ups on all four major networks, including a variety series (The Brady Bunch Hour. ABC. 1977), a "life after" series (The Brady Brides), a holiday special (A Vel)' Brady Christmas), an hour-long dramatic series (The Bradys), and a made-for-TV movie (The Brady Bunch in the White House) as well as a stage adaptation (The Real Live Brady Bunch, 1990-94). and feature films (The Brady Bunch Movie and A Very Brady Sequel). Schwartz's Big John, Little John series was also no­ table for bringing the nonanimated/filmed sitcom to Saturday morning children's television well before Pee-Wees Playhouse and Saved by the Bell.