SeaWorld was founded in 1964 by Milton Shedd, Ken Norris, David Demott and George Millay. The four graduates of UCLA originally set out to build an underwater restaurant and marine life show. When the underwater restaurant concept was deemed unfeasible, they scrapped those plans and decided to build a park instead, and SeaWorld San Diego was opened on March 21, 1964. With a few dolphins, sea lions, six attractions and 22 acres (89,000 m2), the park proved to be a success and more than 400,000 guests visited in the first 12 months.

SeaWorld was privately held before going public in 1968. The second SeaWorld location, SeaWorld Ohio, opened in 1970, followed by SeaWorld Orlando in 1973, and SeaWorld San Antonio in 1988. The partnership later sold SeaWorld Ohio to Six Flags in January 2001. Harcourt Brace Jovanovich owned the parks between 1976 and 1989, when Anheuser-Busch Companies, Inc. purchased them. After InBev acquired Anheuser-Busch, it sold SeaWorld San Diego and the rest of the company's theme parks to the Blackstone Group in December 2009.