professional football championship with a 9–0–1 record. Decatur/Chicago Staleys In August 1920, the American Professional Football Association (APFA, later renamed the National Football League) was organized. Chamberlin signed with George Halas' 1920 Decatur Staleys team that compiled a 10–1–2 record and finished second in the APFA. At the end of the 1920 season, Chamberlin was selected as a first-team end on the first All-Pro Team. In 1921, Chamberlin played as a center fielder for the Staleys baseball team during the summer, and he remained with the organization as the Staleys football team moved to Chicago and won the APFA championship with a 9–1–1 record. On December 3, 1921, before a crowd of 13,000 in Chicago, the Staleys defeated the first-place Buffalo All-Americans in what was touted as the championship game. In the victory over Buffalo, Chamberlain intercepted a pass and returned it 90 yards for the game-winning touchdown. George Halas, who coached Chamberlin with the Staleys, wrote in 1957: "Chamberlin was the best 2-way end I've ever seen. He was a tremendous tackler on defense and a triple-threat performer on offense." Canton/Cleveland Bulldogs In 1922, Chamberlin joined the Canton Bulldogs in multiple roles as a player, head coach, team captain, and part owner. He strengthened the team in the off-season by signing guard Tarzan Taylor, with whom he had played on the Staleys, and tackle Link Lyman, an All-American who played at Chamberlin's alma mater, Nebraska. Chamberlin led the 1922 Bulldogs to an NFL championship with an undefeated 10–0–2 record. The team shut out nine of twelve opponents and allowed only 15 points in 12 games. Three players from the 1922 Bulldogs (Chamberlin, Lyman, and Pete Henry) were later inducted into the Pro Football Hall of Fame. Chamberlin led the team in scoring with seven touchdowns, two of them on interception returns. He played at the halfback position in the first game of the season and at end for the remaining 12 games; he reportedly "played every minute of the thirteen games." Chamberlin returned to the Bulldogs as player/coach the following year. The 1923 team had another undefeated season (11-0-1), shut out eight of twelve opponents, outscored all opponents by a combined total of 246 to 19, and won its second consecutive NFL championship. After the season, Chamberlin was selected as a first-team All-Pro player by Collyer's Eye magazine. In August 1924, Cleveland jeweler Samuel Deutsch bought the Canton Bulldogs