- Sep 4 Man o' War wins the 1 5/8-mile Lawrence Realization Stakes at Belmont Park by 100 lengths, the largest winning margin in modern thoroughbred racing history; world record time 2.40.8
Dempsey KOs Miske
Sep 6 Jack Dempsey KOs Billy Miske in 3 for heavyweight boxing title 1st radio broadcast of a prizefight
US Men's Tennis Open
Sep 6 US National Championship Men's Tennis, Forest Hills NY: Bill Tilden wins first of 6 straight US singles titles; beats Bill Johnston 6-1, 1-6, 7-5, 5-7, 6-3
- Sep 12 VII Summer Olympic Games close in Antwerp, Belgium
- Sep 17 National Football League is born in Canton, Ohio; 12 teams pay $100 each to join American Professional Football Association; renamed the NFL in 1922
- Sep 22 Chicago grand jury convenes to investigate charges that 8 White Sox players conspired to fix the 1919 World Series
- Sep 25 US National Championship Women's Tennis, Philadelphia CC: Molla Bjurstedt Mallory beats Marion Zinderstein 6-3, 6-1 for her 5th US singles crown
- Sep 28 8 Chicago White Sox baseball players are indicted by a grand jury, charged with fixing 1919 World Series; infamous "Black Sox scandal"
- Sep 29 Yankees slugger Babe Ruth sets then-MLB home run season record at 54 with a 9th inning shot off Dave Keefe in New York's 7-3 win at the Philadelphia A's
Baseball Players
Basketball Stars
Boxers
Footballers
NFL Stars
Tennis Champions