1920

• The American Professional Football Association was officially organized to begin play in the fall.

Here are the original teams:

• Akron Professionals

• Buffalo All-Americans

• Canton Bulldogs

• Chicago Cardinals

• Chicago Tigers

• Cleveland Tigers

• Columbus Panhandles

• Dayton Triangles

• Decatur Staleys

• Detroit Heralds

• Hammond Pros

• Muncie Flyers

• Rochester (N.Y.) Jeffersons

• Rock Island Independents

• The Chicago Tigers folded after the 1920 season.

1921

• The Decatur Staleys moved to Chicago but retain the name Staleys .

The following teams joined the APFA for the 1921 season:

• Cincinnati Celts

• Evansville Crimson Giants

• Green Bay Packers

• Louisville Brecks

• Minneapolis Marines

• New York Brickleys Giants

• Tonawanda Kardex

• Washington Senators

The following teams folded after the 1921 season:

• Cincinnati Celts

• Cleveland Tigers

• Detroit Heralds

• Muncie Flyers

• New York Brickleys Giants

• Tonawanda Kardex

• Washington Senators

1922

• The APFA changes its name to the National Football League.

• The Chicago Staleys change their name to the Chicago Bears.

The following teams joined the NFL for the 1922 season:

• Marion Oorang Indians

• Milwaukee Badgers

• Racine Legion

• Toledo Maroons

The following teams folded after the 1922 season:

• Columbus Panhandles

• Evansville Crimson Giants

1923

The following teams joined the NFL for the 1923 season:

• Cleveland Indians

• Columbus Tigers

• Duluth Kelleys

• St. Louis All-Stars

The following teams folded after the 1923 season:

• Canton Bulldogs

• Cleveland Indians

• Louisville Brecks

• Marion Oorang Indians

• Racine Legion

• St. Louis All-Stars

• Toledo Maroons

1924

• The Buffalo All-Americans changed their name to the Buffalo Bisons.

The following teams joined the NFL for the 1924 season:

• Cleveland Bulldogs

• Frankford Yellow Jackets

• Kansas City Blues

• Kenosha Maroons

The following teams folded after the 1924 season:

• Columbus Tigers

• Kenosha Maroons

• Minneapolis Marines

1925

• The Kansas City Blues changed their name to the Kansas City Cowboys.

The following teams joined the NFL for the 1925 season:

• The Canton Bulldogs returned to the NFL after being inactive during the 1924 season.

• Detroit Panthers

• New York Giants

• Providence Steam Roller

• Pottsville Maroons

The following teams folded after the 1925 season:

• Cleveland Bulldogs

• Rochester Jeffersons

• The Rock Island Independents left the NFL for the AFL.

1926

• The Akron Pros changed their name to the Akron Indians.

• The Buffalo Bisons changed their name to the Buffalo Rangers.

• The Duluth Kelleys changed their name to the Duluth Eskimos.

The following teams joined the NFL for the 1926 season:

• Brooklyn Lions

• Hartford Blues

• Los Angeles Buccaneers

• Racine Tornadoes (formerly the Racine Legion) return to the NFL.

• The Louisville Colonels (formerly the Louisville Brecks) return to the NFL.

The following teams folded after the 1926 season:

• Akron Indians

• Brooklyn Lions

• Buffalo Rangers

• Canton Bulldogs

• Columbus Tigers

• Detroit Panthers

• Hartford Blues

• Hammond Pros

• Kansas City Cowboys

• Los Angeles Buccaneers

• Louisville Colonels

• Milwaukee Badgers

• Racine Tornadoes

1927

The following teams joined the NFL for the 1927 season:

• Cleveland Bulldogs

• New York Yankees

The following teams folded after the 1927 season:

• Buffalo Bison

• Cleveland Bulldogs

• Duluth Eskimos

1928

The following team joined the NFL for the 1928 season:

• Detroit Wolverines

The following team folded after the 1928 season:

• New York Yankees

1929

The following teams joined the NFL for the 1929 season:

• Boston Bulldogs

• Buffalo Bisons

• Minneapolis Red Jackets

• Orange Tornadoes

• Staten Island Stapletons

The following teams folded after the 1929 season:

• Dayton Triangles

• Buffalo Bisons

• Boston Bulldogs