Events in Sport
- Dec 9 1939 NFL Draft: Ki Aldrich from TCU first pick by Chicago Cardinals
- Dec 10 CFL Grey Cup: In repeat of last year, Toronto Argonauts defeat Winnipeg Blue Bombers, 30-7 to retain Championship
NFL Championship
Dec 11 National Football League Championship, Polo Grounds, NYC: New York Giants beat Green Bay Packers, 23-17; record title game attendance 48,120

Mel Hein
- Dec 14 Major League Baseball agrees on use of a standard ball; disagrees on increasing rosters from 23 to 25 players, although Commissioner Judge Landis eventually decides on 25
- Dec 14 Will Harridge is elected to a 10-year-term as AL president
- Dec 20 Boston Bruins rookie goalie Frankie Brimsek records his 3rd straight shutout with a 3-0 win over the New York Americans, making it his incredible sixth shutout in his first 8 NHL games
- Dec 26 Tom Goddard takes a cricket hat-trick for England v South Africa
- Dec 28 Paul Gibb scores 106 on Test Cricket debut v South Africa
Birthdays in Sport
- Dec 1 Bill Playle, New Zealand cricket batsman (8 Tests), born in Palmerston North, New Zealand (d. 2019)
- Dec 2 Luis Artime, Argentine soccer striker and manager (25 caps; River Plate), born in Parque Civit, Argentina
- Dec 4 Frank Myler, English rugby league stand-off (24 caps Great Britain, 1 England; Widnes, St. Helens) and coach (Widnes, Swinton, Oldham), born in Widnes, England (d. 2020)
- Dec 4 Richard Meade, British equestrian (3 x Olympic gold eventing 1968, 72; World C'ship gold team 1970, 82), born in Chepstow, Monmouthshire, Wales (d. 2015)
- Dec 9 Deacon Jones, American Pro Football Hall of Fame defensive end (8 × Pro Bowl; 5 × First-team All-Pro; LA Rams, SD Chargers), born in Eatonville, Florida (d. 2013)
- Dec 10 Bill Mathis, American football halfback (AFL All Star 1961, 63; New York Titans/Jets), born in Rocky Mount, North Carolina (d. 2020)
- Dec 11 Fred Cox, American NFL kicker (NFL champion 1969; Pro Bowl 1970; Minnesota Vikings all-time leading scorer), born in Monongahela, Pennsylvania (d. 2019)
- Dec 13 Tom Shaw, American golfer (The Tradition 1993), born in Wichita, Kansas
- Dec 15 Bob Foster, American boxer (world light-heavyweight champion 1968-74), born in Borger, Texas (d. 2015)
- Dec 16 Frank Deford, American sportswriter
- Dec 17 Peter Snell, New Zealand athlete (Olympic gold 800m 1960, 64; 1,500m 1964), born in Opunake, New Zealand (d. 2019)
- Dec 22 Matty Alou, Dominican baseball outfielder (NL batting champion 1966; MLB All-Star 1968-69), born in Haina, Dominican Republic (d. 2011)
- Dec 28 Pachín, Spanish soccer defender (8 caps; Real Madrid) and manager (Osasuna, Levante, Granada), born in Torrelavega, Spain (d. 2021)
- Dec 29 Wayne Huizenga, American businessman, CEO (Waste Management, Blockbuster), and sports team owner (Miami Dolphins, Florida Panthers, Florida Marlins), born in Evergreen Park, Illinois (d. 2018)
- Dec 29 Harvey Smith, British showjumper, born in West Riding, Yorkshire, England
- Dec 29 Gianluigi Saccaro, Italian fencer (Olympic gold épée team 1960; silver épée team 1964; bronze épée 1968), born in Milan, Italy (d. 2021)
- Dec 31 Atje Keulen-Deelstra, Dutch speed skater (world champ, born in Grou, Netherlands (d. 2013)