Texas and Arkansas native Lamar Hunt brought the Dallas Texans NFL team, which he owned, to Kansas City, Missouri, in 1963, renaming the franchise the Kansas City Chiefs. He founded an operating company in the region called MId-America Enterprises, which focused on real estate, mining, and entertainment. Worlds of Fun was conceptualized and developed by Hunt, his business partner Jack Steadman, and theme park designer Randall Duell. Construction on the park began in November 1971 and was completed over 17 months at an estimated cost of $20 million. The park opened on May 26, 1973. It is located at the northern edge of a vast industrial complex in the bluffs above the Missouri River in Clay County, Missouri. At the time it opened, numerous projects across Kansas City were being built, including Kansas City International Airport, Kemper Arena (now called Hy-Vee Arena), and the Truman Sports Complex. The park was originally planned to complement a 500-acre (2.0 km2) hotel and entertainment complex, but a lagging economy during the park's early years derailed the idea.

In 1974, the first addition to Worlds of Fun was the 4,000-seat Forum Amphitheater, which opened in the Europa section of the park. In 1976, a new section opened in honor of the United States Bicentennial – the 200th anniversary of the signing of the Declaration of Independence–and was named Bicentennial Square. The new section included the debut of Screamroller from Arrow Dynamics, which was a replica of the first modern looping roller coaster, Corkscrew, that opened a year earlier at Knott's Berry Farm.

In 1982, Oceans of Fun opened next door as the largest water park in the world. In the same year, a sub-world named "River City" was opened in Americana, adjacent to the East Asia section (then referred to as the Orient section). Screamroller was transformed into Extremeroller the following year, which featured stand-up trains instead of the original sit-down models, making it the first looping, stand-up roller coaster in North America. Several years later, in 1989, Worlds of Fun ended the decade with the addition of Timber Wolf, a wooden roller coaster that initially ranked high in several national polls.

Cedar Fair LP purchased Worlds of Fun in 1995 for $40 million. The new owners invested $10 million with the addition of Mamba, a D.H. Morgan Manufacturing steel hypercoaster, to the park's attraction lineup in 1998.

On July 1, 2024, a merger of equals between Cedar Fair and Six Flags was completed, creating Six Flags Entertainment Corporation.