The AAFC operated from 1946 to 1949, with Paul Brown's Cleveland Browns claiming the championship title each year. Following the AAFC's dissolution, the Browns, San Francisco 49ers, and the original Baltimore Colts joined the NFL in 1950. The initial Colts franchise folded after a single season before being re-established as a new team in 1953.

While the AAFC published a statistical supplement after its final season in 1949 that included single-game records, comprehensive scoresheets from all individual games were unavailable then. However, these score sheets have since been recovered. These historical statistics have now been officially incorporated into the NFL's records following consultations with the Elias Sports Bureau and the Pro Football Hall of Fame. This decision mirrors the NFL's integration of American Football League (AFL) statistics into its official records after the two leagues merged in 1970.

The NFL absorbed the Browns, the San Francisco 49ers, and a franchise called the Baltimore Colts (not connected to the late 1950s-1980s Baltimore Colts or the modern Indianapolis Colts).

Other teams such as the Chicago Rockets, Miami Seahawks, New York Yankees, Brooklyn Dodgers, Buffalo Bisons, and Los Angeles Dons folded.