"The Ballad of Gilligan’s Isle" is the opening theme song written by Sherwood Schwartz and George Wyle created to set the premise of "Gilligan's Island." Considered the most famous and most recognized TV theme song in television history, it was composed to replace the show's original calypso theme song created by future film composer John Williams, most famous for the signature scores of the "Superman," "Star Wars" and "Close Encounters" soundtracks (at this point. As a result of the changing theme, the original length of the S.S. Minnow's voyage was changed from "a six-hour ride" to "a three-hour tour". Williams was also credited as the composer of the incidental music for the show from 1964 to 1965, replaced by Gerald Fried for the remaining 1965 to 1967 seasons.

After the first season, the theme song was re-edited from "and the rest" to "the Professor and Mary Ann", who were previously considered "second-billed co-stars" (meaning they received acknowledgement during the closing credits only), but Bob Denver, who played Gilligan, personally went to the studio and asked that the characters of Russell Johnson and Dawn Wells be added to the opening credits. Since his contract allowed him to choose where he could be placed in the credits, he was willing to have his name placed last to show his support to his co-stars. Although the studio was resistant at first, they relented and had the opening re-shot with the altered lyrics and the faces of Johnson and Wells added to the sequence; Denver remained the first actor credited. (Coincidentally, the sequence was also updated as the series was being converted to color.) According to Dawn Wells, it wasn't until years after the show ended that Denver's efforts were revealed.
During the first season version, the theme song was recorded by The Wellingtons, who went on to appear in the Second Season episode, Don't Bug the Mosquitoes, but during the Second and Third Season , it was re-recorded by The Eligibles.

All I had to work with was the music backing track with no voices so, I sang along with myself to create the illusion of a trio or group and added the harmonies for "the millionaire and his wife."