January 22 – The New York Yankees announce they will put numbers on the backs of their uniforms, becoming the first baseball team to start continuous use of the numbers. The first numbers are based on positions in the batting order; thus, Babe Ruth will wear number 3 and Lou Gehrig number 4. In a few weeks, the Cleveland Indians announce that they, too, will put numbers on the uniforms. By 1931, all American League teams will use them. It will be 1933 before all National League players are numbered.
July 6 – After losing 10-6 in the opener of a double header against the Philadelphia Phillies, the St. Louis Cardinals score ten runs in the first inning on their way to a 28-6 victory in the second game. The two teams combine to collect a record 73 hits in a double header.
July 24 – With a win over the New York Giants and a 6-4 loss by the Pittsburgh Pirates at the hands of the Brooklyn Robins, the Cubs claim sole possession of first place in the National League by half a game. They hold first place the remainder of the season.
August 11 – Babe Ruth hit his 500th career home run in the second inning off Willis Hudlin at Cleveland's League Park. The homer was Ruth's 30th of the year, but it wasn't enough as the Indians beat the Yankees, 6-5.
September 21 – Connie Mack's Philadelphia Athletics win their 100th game of the season, 10-7, over the Detroit Tigers.
October 5 – The Philadelphia Phillies' Lefty O'Doul goes six-for-nine in a double header with the New York Giants on the last day of the season for the Phillies, ending the season with a .398 batting average.
October 8 – Howard Ehmke, who was in the twilight of his career, and had made only eleven appearances for the Philadelphia Athletics during the regular season, is handed the ball for the first game of the 1929 World Series. He gives up just one unearned run in the ninth inning to lead the A's to a 3-1 victory over the Chicago Cubs.
October 11 – Philadelphia Athletics game two starting pitcherGeorge Earnshaw is the starter in game three of the World Series as well, and pitches all nine innings. The Cubs win their only game of the World Series, 3-1.
October 12 – Behind 8-0, the Philadelphia Athletics explode for ten runs in the seventh inning to win game four of the World Series, 10-8. Mule Haas has a three run inside-the-park home run during the inning.
October 14 – Down 2-0 with one out in the ninth inning, the A's score three runs to claim their first World Championship since 1913. Bing Miller delivers the World Series winning hit.
February 1 – Walt Wilmot, who led the National League in homeruns in 1890, and also scored 100 or more runs three times and twice collected 70 or more stolen bases.
February 2 – Thorny Hawkes, 76, second baseman for the 1879 Troy Trojans and the 1884 Washington Nationals.
February 2 – Mike Walsh, 78, Irish umpire in the National inaugural season in 1876, who later officiated in the National Association and the American Association and also managed the 1884 Louisville Colonels.
February 11 – Dutch Ulrich, 29, pitcher or the Philadelphia Phillies from 1925 through 1927.
February 13 – Joe Straub, 71, German catcher who played in part of three seasons with the Troy Trojans, Philadelphia Athletics and Columbus Buckeyes between 1880 and 1883.
February 26 – Jim Moroney, 45, pitcher for the Boston Beaneaters, Philadelphia Phillies and Chicago Cubs in part of three seasons spanning 1906–1912.
March 1 – Ed Foster, 43, pitcher for the 1908 Cleveland Naps.
March 2 – Tom Smith, 57, pitcher for the Boston Beaneaters, Philadelphia Phillies, Louisville Colonels and St. Louis Browns in four seasons between 1894–1898.
March 5 – Lou Hardie, 64, catcher/outfielder for the Philadelphia Quakers, Chicago White Stockings, Boston Beaneaters and Baltimore Orioles in parts of four seasons spanning 1884–1891.
March 13 – Sherry Magee, 44, left fielder for the Phillies who led the National League in RBI four times, and in hits, runs and doubles once each; also a batting champion in 1910, while his 441 career stolen bases included 23 thefts of home plate, and later became a NL umpire in 1928.
March 23 – Denny Williams, 32, outfielder who played from 1921 to 1928 for the Cincinnati Reds and Boston Red Sox.
March 25 – Roy Meeker, 28, pitcher for the Philadelphia Athletics and Cincinnati Reds over parts of the three season between 1923 and 1926,
March 30 – Phil Redding, 39, pitcher who played with the St. Louis Cardinals from 1912 to 1923.
May 25 – Harvey Blauvelt, 61, relief ptcher for the 1890 Rochester Broncos.
May 28 – Ollie Beard, 67, shortstop for the Cincinnati Red Stockings/Reds from 1889 to 1890 and third baseman for the 1891 Louisville Colonels; it is claimed that his family invented the Kentucky dish, Burgoo.
July 2 – Buck Hooker, 48, pitcher who played from 1902 through 1903 for the Cincinnati Reds.
July 3 – Bill McClellan, 73, second baseman/shortstop for five teams between 1878 and 1888, primarily for the Brooklyn Grays/Bridegrooms from 1885 to 1888.
July 5 – Ted Sullivan, 78, Irish outfielder/manager in the 1880s, who led the St. Louis Maroons of the Union Association to an astonishing 94-19 record in the 1884 season.
July 8 – Joe Kappel, 72, backup outfielder/infielder for the 1884 Philadelphia Quakers and the 1890 Philadelphia Athletics.
July 9 – Pete Cassidy, 56, first baseman who played with the Louisville Colonels, Brooklyn Superbas and Washington Senators in parts of two seasons spanning 1896–1899.
July 12 – Jack Cronin, 55, pitcher who played seven seasons with seven teams in two different leagues between 1895 and 1904.
July 19 – Tom O'Rourke, 63, backup catcher for the Boston Beaneaters, New York Giants and Syracuse Stars in parts of four seasons spanning 1887–1890.
July 20 – Rupert Mills, 36, first baseman for the 1915 Newark Peppers of the Federal League, who, due to a term in his contract, "played" the non-existent 1916 season by showing up at the ballpark each day in uniform and ready to play, thereby earning his 1916 salary.
July 21 – Frank Gilmore, 65, pitcher who played from 1886 through 1888 for the Washington Nationals.
July 24 – George Miller, 76, backup catcher for the 1877 Cincinnati Reds and the 1884 Cincinnati Red Stockings.
August 5 – Tony Brottem, 38, catcher/first baseman for the St. Louis Cardinals. Washington Senators and Pittsburgh Pirates during three seasons between 1916 and 1921.
August 6 – Andy Cusick, 71, Irish catcher who played from 1884 through 1887 with the Wilmington Quicksteps and the Philadelphia Quakers.
August 8 – Dan Minnehan, 63, third baseman for the 1895 Louisville Colonels.
August 11 – Red Long, 52, Canadian pitcher for the 1902 Boston Beaneaters.
August 15 – Jack Manning, 75, right fielder/pitcher for eight teams during 12 seasons in three different leagues, who in 1884 became the third player the collect a three-homerun game, behind Ned Williamson and Cap Anson.
August 27 – Charlie Snow, 80, catcher for the 1874 Brooklyn Atlantics.
August 28 – Ed Flynn, 65, catcher for the 1887 Cleveland Blues.
September 2 -Bert Blue, 51, backup catcher who played for the St. Louis Browns and the Philadelphia Athletics during the 1908 season.
September 22 – Ice Box Chamberlain, 61, pitcher who played for six teams in 10 seasons between 1886 and 1896, who led the American Association in shutouts (1890) and ranks 64th on the all-time complete games list (265).
September 25 – Miller Huggins, 50, Hall of Fame manager who guided the New York Yankees to its first six American League pennants (1921–23; 1926–28) and three World Series titles (1923, 1927–28), including the legendary 1927 Murderers Row squad.
October 22 – Walt Lerian, 26, promising catcher of the Philadelphia Phillies from 1928 through 1929, who died just days after the conclusion of the 1929 season, when he was hit by out-of-control truck while standing on a Baltimore street.
October 22 – Jim Manning, 67, outfielder/infielder for the Boston Beaneaters, Detroit Wolverines and Kansas City Cowboys in parts of five seasons spanning 1884–1889, who later managed the Washington Senators during the inaugural season of the American League in 1901.
November 8 – Red Bittmann, 67, second baseman for the 1889 Kansas City Cowboys.
November 10 – Mark Baldwin, 66, pitcher for five teams in three different leagues from 1887 to 1893, who posted a 154-165 record and a 3.37 ERA in 346 games, while leading the American Association with 33 wins in 1890 and for the most innings pitched in 1889 (513.2) and 1890 (492), and collected 296 complete games, which ranks him 46th on the all-time career list.
November 11 – Sam White, 36, English catcher for the Boston Braves during the 1919 season.
November 14 – Joe McGinnity, 58, Hall of Fame pitcher whose 246 victories included eight 20-win seasons, while leading the National League in wins five times, in innings four times and games six times, as his 31 wins for the 1903 New York Giants included three complete August doubleheaders, and also won 239 games in the minor leagues.
November 15 – Billy Nash, 64, prominent third baseman for the Richmond Virginians, Boston Beaneaters and Philadelphia Phillies from 1884 through 1898, who posted a .275 batting average with 60 home runs and 979 runs batted in for 1550 games, while scoring 100 runs four times and collecting 110 or more RBI two times, also leading the National League in putouts, double plays and fielding average four times each.
November 20 – Babe Doty, 61, pitcher who played for the 1890 Toledo Maumees.
November 20 – Jim Powell, 70, first baseman who played from 1884 to 1885 with the Richmond Virginians and the Philadelphia Athletics.
November 29 – Jimmy Whelan, 39, who appeared as a pinch-hitter in one game for the 1913 St. Louis Cardinals.