The 1940 World Series matched the Cincinnati Reds against the Detroit Tigers, with the Reds winning a closely contested seven-game series. The victory secured the Reds the second championship in their franchise history and came 21 years after their victory over the scandal-tainted Chicago White Sox in 1919. This would be the Reds' last World Series championship for 35 years despite appearances in 1961, 1970, and 1972. Meanwhile, Bill Klem worked the last of his record 18 World Series as an umpire.

William Joseph Klem, known as "the Old Arbitrator", was an American baseball umpire who worked in Major League Baseball from 1905 to 1941, spending his entire career in the National League (NL). He worked 18 World Series, which is a major league record. Klem was posthumously inducted into the Baseball Hall of Fame in 1953.