After Walt Disney passed on in 1966, the Sherman Brothers viewed the song as his "theme song" because of his optimism and his visions of the future.
The Carousel of Progress was subsequently moved to Walt Disney World's Magic Kingdom, where it opened on January 15, 1975. However, General Electric requested that a new song be used for the show, so the Sherman Brothers wrote "The Best Time of Your Life" for this updated version of the show. General Electric ceased sponsorship of the Carousel of Progress in 1985, but "The Best Time of Your Life" was still used until 1993, at which point the show closed to be updated again for that park's New Tomorrowland. It reopened in 1994 as Walt Disney's Carousel of Progress, and an updated "There's a Great Big Beautiful Tomorrow" was again the theme song. Arrangements of "The Best Time of Your Life" and "There's a Great Big Beautiful Tomorrow" can be heard in the current background area music for Tomorrowland at Disneyland and the Magic Kingdom.
Meanwhile, at Disneyland, America Sings ended its run in 1988, after which many of the Audio-Animatronic characters were recycled into Splash Mountain and Star Tours, leaving the Carousel Theater empty. It would lay dormant for more than ten years, when a new version of Epcot's Innoventions was installed in it. "There's a Great Big Beautiful Tomorrow" was chosen as the theme song of Innoventions, with an instrumental version used as the area music and a lively rendition with new lyrics is sung by Tom Morrow (voiced by Nathan Lane), as a tribute to the attraction which originally occupied the Carousel Theater.
A cover version of the song, by They Might Be Giants appears as part of the soundtrack to the film, Meet the Robinsons. It also can be heard at the end of Say Hello to ASIMO, an attraction at the Honda ASIMO Theater in Disneyland. It is also used as the score for the EPCOT and Florida Project film. ESPNU also used the song to promote their National College Football Signing Day coverage in 2015. This song also makes an appearance in the 2015 film Tomorrowland, when a young Frank Walker arrives at the 1964 World's Fair.