Many of the series' ideas originated in The Intertidal Zone, an unpublished educational book that Hillenburg created in 1989 to teach his students about undersea life. He began developing SpongeBob SquarePants into a television series in 1996 following the cancellation of Rocko's Modern Life. He turned to Tom Kenny, who had worked with him on that series, to voice the title character. SpongeBob was originally going to be named SpongeBoy, and the series called SpongeBoy Ahoy!; both of these were changed as the name was already trademarked.
Nickelodeon held a preview for the series in the United States on May 1, 1999, after it aired the 1999 Kids' Choice Awards. The series officially premiered on July 17, 1999. It has received worldwide critical acclaim since its premiere and had gained enormous popularity by its second season. A feature film, The SpongeBob SquarePants Movie, was released in theaters on November 19, 2004. A second film adaptation, The SpongeBob Movie: Sponge Out of Water, followed on February 6, 2015. A third film and prequel to the television series, The SpongeBob Movie: Sponge on the Run, is expected to be released in Canadian theaters on August 14, 2020 followed by a premiere on video-on-demand and CBS All Access in 2021. In 2018, the series began airing its twelfth season; it was renewed for a thirteenth season on July 17, 2019. As of July 30, 2020, all prior seasons of the show are available on CBS All Access.