- Sep 1 Clinton Portis, American football running back (Pro Bowl 2003, 08; Denver Broncos, Washington Redskins), born in Laurel, Mississippi
- Sep 2 Chris Tremlett, English cricketer
- Sep 4 Richard Garcia, Australian soccer midfielder/forward (17 caps; West Ham United, Colchester United, Hull City, Perth Glory) and coach (Perth Glory), born in Perth, Australia
- Sep 5 Drew Carter, American football player, born in Solon, Ohio
- Sep 5 Filippo Volandri, Italian tennis player, born in Livorno, Italy
- Sep 6 Mark Teahen, American-Canadian baseball player, born in Redlands, California
- Sep 7 Gökhan Zan, Turkish footballer, born in Antakya, Hatay, Turkey
- Sep 8 Morten Gamst Pedersen, Norwegian soccer midfielder (83 caps; Blackburn Rovers 288 games, Tromsø IL), born in Vadsø, Norway
- Sep 11 Andrea Dossena, Italian footballer (Piacenza), born in Lodi, Italy
- Sep 12 Jered Guzman, American pairs skater (with partner Natalie Vlandis), born in Garden Grove, California
- Sep 13 Antonio Lopez, Spanish footballer (Atlético Madrid), born in Benidorm, Spain
- Sep 13 Koldo Fernández, Spanish cyclist, born in Vitoria-Gasteiz, Basque Country, Spain
- Sep 17 Bakari Koné, Ivorian footballer
- Sep 17 Casey Janssen, American baseball player
- Sep 17 Francis Manioru, Solomon Island sprinter
- Sep 19 Damiano Cunego, Italian cyclist (Nippo–Vini Fantini team), born in Cerro Veronese, Italy
- Sep 19 Rick DiPietro, American ice hockey player, born in Winthrop, Massachusetts
- Sep 20 Feliciano López, Spanish tennis player
- Sep 20 Jordan Tata, American baseball player
- Sep 23 Robert Doornbos, Dutch race car driver
- Sep 24 Drew Gooden, National Basketball Association player and broadcaster, born in Oakland, California
- Sep 24 Ryan Briscoe, American auto racer (24 Hours of Daytona 2020; 12 Hours of Sebring LMP2 class 2013; Petit Le Mans LMP2 class 2008, 13), born in Sydney, Australia
- Sep 25 Jason Bergmann, American baseball player, born in Neptune City, New Jersey
- Sep 25 Rocco Baldelli, American baseball player, born in Woonsocket, Rhode Island
Serena Williams (42 years old)
Sep 26 American tennis player (23 x Grand Slam singles titles; Tour Finals x 5; Olympic gold 2012; 16 x GS doubles titles), born in Saginaw, Michigan
- Sep 27 Brendon McCullum, New Zealand cricketer
- Sep 27 Lakshmipathy Balaji, Indian cricketer
- Sep 28 Jorge Guagua, Ecuadorian soccer defender (63 caps; El Nacional), born in Esmeraldas, Ecuador
- Sep 28 José Calderón, Spanish basketball point guard (captain Spain gold FIBA World C'ship 2006; Olympic silver 08, 12; NBA: Toronto, Detroit, Dallas, NY Knicks; Cleveland), born in Villanueva de la Serena, Spain
- Sep 30 Dominique Moceanu, American gymnast (World-silver-95, Olympic gold 1996), born in Los Angeles, California
About September 1981
How Old? 42 years old
Generation: Millennial
Leap Year: No
Baseball Players
Basketball Stars
Boxers
Footballers
NFL Stars
Tennis Champions