The National Football League (NFL) was formed in 1922 out of the American Professional Football Association (APFA), which was founded in 1920.
The Chicago Cardinals were founded by Chris O’Brien in 1898, using the name Cardinals starting in 1901. In 1920, the Cardinals became charter members in the APFA, joining the NFL in 1922. In 1960, the team moved to St. Louis for 28 years. In 1988, the Cardinals moved to Phoenix; in 1994, the team started calling themselves the Arizona Cardinals.
The Green Bay Packers were founded in 1919 by George Calhoun and Curly Lambeau, joining the APFA in 1921 and the NFL in 1922.
The Chicago Bears were founded in 1920 by George Halas, who helped form the APFA, as the Decatur Staleys. In 1922, he joined the NFL, after moving the team to Chicago in 1921 and calling them the Bears in 1922.
The Philadelphia Eagles joined the NFL in 1924 as the Frankford (PA) Yellow Jackets. Owners Bert Bell and Lud Wray moved the team to Philadelphia as the Eagles in 1933.
The New York Giants, owned by Tim Mara, joined the NFL in 1925.
The Detroit Lions started out in the NFL as the Portsmouth (OH) Spartans in 1930. Owner George Richards moved the team to Detroit in 1932, calling them the Lions.
The Washington Redskins, founded by George Preston Marshall, joined the NFL in 1932 as the Boston Braves. In 1933, he changed their name to the Redskins and in 1937, he moved them to Washington, D.C.
The Pittsburgh Steelers joined the league in 1933 as the Pirates. Owner Art Rooney changed their name to the Steelers in 1940.
The Cleveland Rams started out in the American Football League (of the 1930′s) in 1936, joining the NFL in 1937. They moved to Los Angeles in 1946 and they moved again in 1995 to St. Louis.
The San Francisco 49ers started out in the All-America Football Conference (AAFC) in 1946, joining the NFL in 1950.
The Cleveland Browns were a charter member of the AAFC in 1946 under Paul Brown, joining the NFL in 1950. After team owner Arthur B. Modell moved the Browns to Baltimore in 1996, calling them the Ravens, a new Cleveland Browns franchise rejoined the NFL in 1999.
The Baltimore Colts started out as the Miami Seahawks of the AAFC when, in 1947, they moved to Baltimore as the Colts. In 1950, they joined the NFL, but after two 1-11 seasons they disbanded. In 1953, the Dallas Texans under Carroll Rosenbloom moved the team to Baltimore and again called them the Colts.
The Dallas Cowboys joined the NFL in 1960 as an expansion team.
The Buffalo Bills became a charter member of the American Football League (AFL) in 1960 under founder Ralph C. Wilson, joining the NFL in the merger of the two leagues in 1970.
The New England Patriots were a charter member of the AFL in 1960 as the Boston Patriots. After joining the NFL in 1970, they moved to Foxboro, MA in 1971, calling themselves the New England Patriots.
The New York Jets started out as the New York Titans, a charter member of the AFL, in 1960. In 1963, they changed their name to the Jets, joining the NFL in 1970.
The Tennessee Titans started out as the Houston Oilers, a charter member of the AFL, in 1960 and joined the NFL in the merger of 1970. In 1997, they moved to Memphis, TN and in 1998 they moved again to Nashville, TN, calling themselves the Titans.
The Denver Broncos joined the AFL as a charter member in 1960. They later joined the NFL in the merger in 1970.
The Kansas City Chiefs started out as the Dallas Texans, a charter member of the AFL, in 1960, moving to Kansas City, MO as the Chiefs in 1963. They later joined the NFL in 1970.
The Oakland Raiders joined the AFL as a charter member in 1960, joining the NFL in the merger in 1970. In 1982, they moved to Los Angeles, only to move back to Oakland in 1995.
The San Diego Chargers started out as the Los Angeles Chargers, a charter member of the AFL in 1960, under the ownership of Barron Hilton. They moved to San Diego in 1961, joining the NFL in 1970.
The Minnesota Vikings joined the NFL in 1961 as an expansion team.
The Atlanta Falcons joined the NFL in 1966 as an expansion team.
The Miami Dolphins joined the AFL in 1966 as an expansion team by founders Joseph Robbie and Danny Thomas. They later joined the NFL in the merger of 1970.
The New Orleans Saints joined the NFL in 1967 as an expansion team.
The Cincinnati Bengals joined the AFL in 1968 as an expansion team under the direction of Paul Brown, joining the NFL in the merger of 1970.
The Tampa Bay Buccaneers joined the NFL in 1976 as an expansion team.
The Seattle Seahawks also joined the NFL in 1976 as an expansion team under the ownership of John Nordstrom.
The Carolina Panthers joined the NFL as an expansion team in 1995 under owner Jerry Richardson.
The Jacksonville Jaguars also joined the NFL as an expansion team in 1995.
The Baltimore Ravens started out as the Cleveland Browns, when Owner Art Modell moved the team to Baltimore in 1996, calling them the Ravens.
The Houston Texans joined the NFL as an expansion team in 2002 under owner Robert McNair.