September 28 – Entering the last day of the season, Ted Williams of the Boston Red Sox was hitting .3995, which would have been good for a .400 average. However, Williams decided to play in both games of a double-header at Shibe Park against the Philadelphia Athletics to make it completely legitimate; he would go 6 for 8 in the two games to leave his average at .406. It remains the last time any player has hit .400 in a season.
September 29 – The Fort Custer team won the national amateur championship of the American Baseball Congress with a 3–2 victory over the Charlotte, North Carolina team. It was the last time the amateur World Series was held until after the war.
November 25 – Cleveland Indians shortstop Lou Boudreau is named as the new team manager. Boudreau takes over for Roger Peckinpaugh, who moves up to the front office as the Indians general manager. At age 24, Boudreau becomes the youngest player to manage a team in the 20th century. Jim McCormick, the first ballplayer born in Scotland to appear in a major league game, managed Cleveland in 1879 at age 23.
November 27 – in a controversial vote, Joe DiMaggio of the New York Yankees is named American League MVP over Ted Williams of the Boston Red Sox (291 points for DiMaggio, 254 for Williams). DiMaggio, who set a 56-game hitting streak record in the season, batted .357 with 30 home runs and led AL in RBI (125). Williams finished even stronger to close the season with a majors lead .406 average and 120 RBI, while led the American League in home runs (37), runs (135), OBP (.553) and SLG (.735). Both the 56-game hitting streak and the .400 plateau have not been touched since then.
January 6 – Charley O'Leary, 58, shortstop for the Detroit Tigers, St. Louis Cardinals and St. Louis Browns between 1904 and 1934, who later coached for many years with the New York Yankees and Chicago Cubs.
January 20 – Jack Lelivelt, 55, outfielder for the Senators, Highlanders, Yankees and Naps from 1909–1914, who also set an International League record with a 42-game hitting streak in 1912, which was broken by Brandon Watson in 2007.
January 24 – Tommy Bond, 84, Irish 19th century pitcher who posted a 234-163 record for six different clubs from 1874 to 1884, and also was the first Triple Crown winner in 1877, while leading the National League with 40 wins, 170 strikeouts, and a 2.11 ERA.
January 25 – Chris Lindsay, 62, first baseman who played from 1905 to 1906 with the Detroit Tigers.
January 28 – John Johnson, 71, pitcher for the 1894 Philadelphia Phillies.
May 1 – Roxy Snipes, 44, pinch-hitter for the 1923 Chicago White Sox.
May 8 – Bill Joyce, 75, third baseman for five teams in eight seasons from 1890–1898 and manager of the New York Giants from 1896 through 1898, who tied for the National League home runs title with Ed Delahanty in 1896 and finished second three times.
May 10 – Jim Pastorius, 59, pitcher from 1906 to 1909 for the Brooklyn Superbas.
May 15 – William Lackey, 70, pitcher for the 1890 Philadelphia Athletics.
May 16 – Art Williams, 63, first baseman/outfielder for the 1902 Chicago Orphans.
May 17 – Bill Husted, 74, pitcher for the 1890 Philadelphia Athletics.
May 19 – Joe Gedeon, 47, second baseman for the Washington Senators, New York Yankees and St. Louis Browns from 1913 to 1920, who led the American League batters with 48 sacrifice hits in 1920, and was one of the eight players suspended for life as result of the Black Sox Scandal.
May 19 – John Schulze, 75, catcher for the 1891 St. Louis Browns.
May 23 – Jack Clements, 76, left-handed catcher for six different teams between 1884 and 1900, who caught 1,073 games and also is credited with being the first catcher to wear a chest protector.
May 25 – Bob Higgins, 54, catcher who played from 1909 to 1912 for the Cleveland Naps and Brooklyn Dodgers.
June 2 – Lou Gehrig, 37, Hall of Fame first baseman who played from 1923 through 1939 for the New York Yankees, a two-time Most Valuable Player and Triple Crown winner, as well as the second player to hit 400 home runs, who retired to end a record 2,130-game playing streak upon being diagnosed with the terminal illness that now bears his name.
June 3 – Andy Cooper, 43, pitcher for the Negro Leagues' Detroit Stars and Kansas City Monarchs.
June 16 – Mike Flynn, 69, Irish catcher who played in one game with the Boston Reds of the American Association.
June 23 – Bill Nelson, 77, pitcher for the 1884 Pittsburg Alleghenys.
July 1 – Harry Adams, 78, umpire both in the National League and American League.
July 3 – Tom McCreery, 66, pitcher/outfielder for five different teams from 1895 to 1903, who is the only player in Major League history to hit three inside-the-park home runs in a single game.
July 4 – Bruce Petway, 55, Negro League catcher in the early 20th century who came to be known as having one of the best throwing arms in the league.
July 6 – Jack Theis, 49, pitcher for the 1920 Cincinnati Reds.
July 6 – Lucky Wright, 61, pitcher for the 1909 Cleveland Indians.
July 7 – Jack Gilbert, 65, outfielder who played with the Washington Senators and New York Giants in the 1898 season and for the Pittsburgh Pirates in 1904.
July 8 – Jack Wadsworth, 73, pitcher who played for the Cleveland Spiders, Baltimore Orioles and Louisville Colonels in part of four seasons spanning 1890–1895.
July 15 – Clarence Currie, 62, pitcher who played from 1902 to 1903 with the Cincinnati Reds, St. Louis Cardinals and Chicago Cubs.
July 15 – Frank Isbell, 65, valuable utility man who played in all nine positions for the Chicago White Sox during 10 seasons 1901 to 1909.
July 17 – Rube Kisinger, 64, pitcher for the 1902–1903 Detroit Tigers, who also led the Buffalo Bisons to their first Eastern League pennant in 1904.
July 20 – Ralph Kreitz, 55, catcher form the 1911 Chicago White Sox.
July 30 – Howie Shanks, 51, who played in all infield and outfield positions from 1912 through 1925 for the Washington Senators, New York Yankees and Boston Red Sox.
July 30 – Mickey Welch, 82, Hall of Fame pitcher and the third hurler in Major League history to reach 300 victories, preceded only by Pud Galvin and Tim Keefe, who on August 28, 1884 struck out the first nine batters he faced to set a record that has remained untouched, while collecting at least 20 wins in nine seasons, including 17 consecutive wins in 1885 en route to a 44-11 record.
July 31 – Jim Byrnes, 61, catcher for the 1906 Philadelphia Athletics.
October 3 – Bert Inks, 70, 19th century pitcher who played from 1891 to 1896 for six different clubs, mainly with the Louisville Colonels.
October 4 – Walt Justis, 58, pitcher for the 1905 Detroit Tigers.
October 13 – George Proeser, 77, who pitched with the Cleveland Blues in 1888 and served as an outfielder for the Syracuse Stars in 1890.
October 24 – Emmett Rogers, 71, catcher for the 1890 Toledo Maumees.
October 25 – Bill Phillips, pitcher for the Pittsburgh Alleghenys and the Cincinnati Reds of the National League in seven seasons between 1890 and 1903, who is best remembered for managing the 1914 Indianapolis Hoosiers to the Federal League pennant.
October 29 – Harvey Hendrick, 43, infielder/outfielder who hit .308 for seven different teams between 1923 and 1934.
October 29 – Wilbur Murdoch, 66, outfielder for the 1908 St. Louis Cardinals.