When the Dallas Texans of the American Football League (AFL) relocated to Kansas City in 1963 and were rebranded as the Chiefs, they played their home games at Municipal Stadium. They originally shared the stadium with the Kansas City Athletics of Major League Baseball, but the Athletics relocated to Oakland, California, after the 1967 season, with the expansion Kansas City Royals being added in 1969.

Municipal Stadium, built in 1923 and mostly rebuilt in 1955, seated approximately 35,000 for football, but as part of the AFL–NFL merger announced in 1966, NFL stadiums would be required to seat no fewer than 50,000 people. Since the City of Kansas City was unable to find a suitable location for a new stadium, Jackson County stepped in and offered a location on the eastern edge of Kansas City near the interchange of Interstate 70 and Interstate 435.

Voters approved a $102 million bond issue in 1967 to build a new sports complex with two stadiums. The original design called for construction of side-by-side baseball and football stadiums with a common roof that would roll between them. The design proved to be more complicated and expensive than originally thought and so was scrapped in favor of the current open-air configuration. The two-stadium complex concept was the first of its kind. The Chiefs staff, led by team general manager Jack Steadman, helped develop the complex.

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