Much Like the American college football game from which it sprung, NFL football is a descendant of rugby football which was imported to the United States from Canada in 1874, and then transformed into American college football after McGill University in Montreal invited Harvard University to Quebec to play a new Canadian version of "rugby football". Arizona Cardinals history Professional football in the United States dates at least to 1892, when an athletic club in Pittsburgh paid William "Pudge" Heffelfinger $500 to take part in a game. Over the next few decades, while Arizona Cardinals history most attention was paid to football at elite colleges on the East Coast, the professional game spread widely in the Midwest, particularly in Ohio where in 1903 the Massillon Tigers, Arizona Cardinals history a strong amateur team, hired four Pittsburgh pros to play in their season-ending game against Akron.

1933 was also the year that black players disappeared from the NFL, just after the acceptance into the league of Boston Braves owner George Preston Marshall, who effectively dissuaded other NFL owners from employing black players until Arizona Cardinals history the mid-forties, and who kept blacks off his team (which eventually became the Washington Redskins) until he was forced to integrate by the Kennedy administration in 1962.

By the end of World War II, pro football began to rival the college game for fans' attention. The spread of the T formation led Arizona Cardinals history to a faster-paced, higher-scoring game that attracted record numbers of fans. In 1945, the Cleveland Rams moved to Los Angeles, becoming the first big-league sports franchise on the West Coast. In 1950, the NFL accepted three teams from the defunct All-America Football Conference, expanding to thirteen clubs.

In the 1950s, pro football finally earned its place as a major sport. The NFL embraced television, giving Americans nationwide a chance to follow stars like Bobby Layne, Paul Hornung, Otto Graham, and Johnny Unitas. The 1958 NFL championship played in Yankee Stadium but blacked out by league Arizona Cardinals history policy in New York drew record TV viewership and made national celebrities out of Unitas and his Baltimore Colts teammates.

The rise of professional football was so fast that by the mid-'60s, it had surpassed baseball as Americans' favorite spectator sport in some surveys. When the NFL history turned down Lamar Hunt's request to purchase either an existing or expansion NFL franchise, he formed the rival American Football League (AFL), in 1960. He encouraged, wheedled, and cajoled seven other like-minded men to form this new league. The group of the eight founders of the AFL teams was referred to as the "Foolish Club." One of them, fellow Texan Bud Adams of Houston, had likewise tried but failed to be granted an NFL franchise. Hunt's goal was to bring professional football to Texas and to acquire an NFL team for the Hunt family.