Originally named the Decatur Staleys, the club was established by the A. E. Staley food starch company of Decatur, Illinois as a company team. This was the typical start for several early professional football franchises. The company hired George Halas and Edward "Dutch" Sternaman in 1920 to run the team. The 1920 Decatur Staleys season was their inaugural regular season completed in the newly formed American Professional Football Association (later renamed the National Football League (NFL) in 1922).
Full control of the team was turned over to Halas and Sternaman in 1921. Official team and league records cite Halas as the founder as he took over the team in 1920 when it became a charter member of the NFL.
The team relocated to Chicago in 1921, where the club was renamed the Chicago Staleys. Under an agreement reached by Halas and Sternaman with Staley, Halas purchased the rights to the club from Staley for US$100.
In 1922, Halas changed the team name from the Staleys to the Bears. The team moved into Wrigley Field, which was home to the Chicago Cubs baseball franchise. As with several early NFL franchises, the Bears derived their nickname from their city's baseball team (some directly, some indirectly – like the Bears, whose young are called "cubs"). Halas liked the bright orange-and-blue colors of his alma mater, the University of Illinois, and the Bears adopted those colors as their own, albeit in a darker shade of each (the blue is Pantone 5395, navy blue, and the orange is Pantone 1665, similar to burnt orange).
The Staleys/Bears dominated the league in the early years. Their rivalry with the Chicago Cardinals, the oldest in the NFL (and a crosstown rival from 1920 to 1959), was key in four out of the first six league titles. During the league's first six years, the Bears lost twice to the Canton Bulldogs (who took two league titles over that span), and split with their crosstown rival Cardinals (going 4–4–2 against each other over that span), but no other team in the league defeated the Bears more than a single time. During that span, the Bears posted 34 shutouts.
The Bears' rivalry with the Green Bay Packers is one of the oldest and most storied in American professional sports, dating back to 1921 (the Green Bay Packers were an independent team until they joined the NFL in 1921). In one infamous incident that year, Halas got the Packers expelled from the league in order to prevent their signing a particular player, and then graciously got them re-admitted after the Bears had closed the deal with that player.