May 10 – In Detroit, it's Ty Cobb day and more than 30,000 pay to see the Detroit Tigers legend in his first appearance at Navin Field in a Philadelphia Athletics uniform. With Eddie Collins on base in the first inning, Cobb drives a double into the overflow crowd to send home Collins for the first run of the game as the Athletics would eventually beat the Tigers 6–3.
May 11 – For the second day in a row, a baseball legend faces his former team for the first time in his career. Rogers Hornsby leads the New York Giants to a 10–1 victory over the St. Louis Cardinals at the Polo Grounds with a home run and five RBIs.
May 14 – Tris Speaker is held hitless by George Uhle in four at-bats in his first game against the Cleveland Indians.
May 22 – The Yankees are in high spirits in Cleveland as they beat the Indians, 7–2, with Babe Ruth hitting his 10th home run of the young season. Ruth's homer is described as a popup that goes over the fence. The Yankees, who wear Indian headdresses during the game, now lead the Al by four and a half games.
Babe Ruth homers for the fourth consecutive game in the fifth inning of the nightcap in Shibe Park. Ruth, who hits his 15th against Jack Quinn and 16th off Howard Ehmke, finishes May with 12 round-trippers. They lose the opener, 10–3. The Athletics' Jimmie Foxx hits his first major league homer; it comes off Urban Shocker.
June 11 – In Cleveland, Babe Ruth hits his 19th and 20th home runs against left-hander Garland Buckeye. The Yankees win, 6–4.
June 12 – For the second day in a row, the Brooklyn Robins defeat the Pittsburgh Pirates by a score of 11–10.
June 16 – The Chicago Cubs complete a twelve-game winning streak to move within a game of first place in the National League.
July 5 – The Boston Red Sox defeat the Philadelphia Athletics, 6–5, to end a fifteen-game losing streak.
July 9 – Johnny Neun steals five bases in the Detroit Tigers' 14–4 victory over the New York Yankees.
July 13 – The Detroit Tigers' Johnny Neun steals home in both games of a doubleheader with the Washington Senators.
July 24 – Babe Ruth hits his 31st home run of the season and his first of 1927 at Comiskey Park; he now has homered in every AL park. The homer, off Tommy Thomas, breaks a 12-day drought for the Bambino. The Yanks win the game, 3–2.
August 16 – At Comiskey Park, Babe Ruth hits a home run against Tommy Thomas. It is Ruth's 37th of the season, but he trails Lou Gehrig, who has 38. The Yankees win the game, 8–1.
The New York Yankees are shut out for the only time all season by Lefty Grove and the Philadelphia Athletics.
Tied for first, the Pittsburgh Pirates sweep a two-game series from the St. Louis Cardinals. They maintain sole possession of first place for the remainder of the season.
September 4 – At Shibe Park in Philadelphia, Babe Ruth hits his 400th career home run and his 44th of the year. The landmark homer comes against Rube Walberg in a 12–2 Yankees win.
September 5 – The Boston Red Sox beat the New York Yankees 12–11 in eighteen innings.
September 6 – Babe Ruth and the Yankees come to Fenway Park for a doubleheader. In game 1, Ruth hits his 45th and 46th home runs of the year against Tony Welzer, and the Yankees win, 14–2. One of Ruth's round-trippers clears the center-field fence and is reputedly the longest ever hit at Fenway. In game 2, the Red Sox win, 5–2, despite Ruth's 47th home run, hit against Jack Russell.
September 7 – Babe Ruth follows up on his three-homer day at Fenway Park with two more. Against Danny MacFayden, Ruth hits his 48th and later cracks number 49 against Slim Harriss. The Yankees win, 12–10, and Ruth now has 8 home runs at Fenway Park.
September 11 – Back At Yankee Stadium, Babe Ruth continues his home run barrage. He hits number 50, this one against Milt Gaston of the Browns; the Yankees lose nonetheless, 6–2.
September 13 – A big day for the Yankees and Babe Ruth. In a doubleheader against the Indians, Ruth hits his 51st home run against Willis Hudlin and his 52nd off Joe Shaute. The Yankees win both games by the score of 5–3 and clinch the AL pennant in their 139th game of the season. In addition, Waite Hoyt wins his 20th game.
September 18 – At Yankee Stadium, New York sweeps Chicago in a doubleheader, 2–1 and 5–1. In the nightcap, against Ted Lyons, Babe Ruth hits his 54th home run of the year. Lou Gehrig weighs in with his third grand slam home run of 1927.
September 22 – At Yankee Stadium, Babe Ruth homers against the Tigers Ken Holloway for his 56th of the season. Earl Combs hits three consecutive triples, and the Yankees win, 8-7.
September 27 – Babe Ruth homers with the bases loaded against Lefty Grove of the Athletics. it is Ruth's 57th of the season. The Yankees win, 7-4.
September 29 – Babe Ruth of the New York Yankees hits two home runs to tie his own 1921 record of 59 home runs as the Yankees beat the Washington Senators, 15–4.
September 30 – With the score tied 2–2 in the eighth inning, and a runner on third, Babe Ruth hits his 60th home run of the season off Washington Senators pitcher Tom Zachary for a Yankees 4–2 victory. Ruth's 60-HR season-record would not be broken for 34 years.
October 2 – Harry Heilmann goes seven-for-nine with a walk in a double header on the final day of the season to miss a .400 batting average for the season by .002.
October 6 – Once again, sloppy play by the Pittsburgh Pirates helps the Yankees cruise to a game two victory as they score runs on an error, wild pitch and hit batsman.
October 7 – A three-run home run by Babe Ruth caps off a six-run seventh inning as the Yankees cruise to an 8–1 victory in game three of the World Series.
October 8 – The New York Yankees defeat the Pittsburgh Pirates, 4–3, in Game 4 of the World Series, to win their second World Championship, four games to none. This was the first sweep by an American League team over the National League. Babe Ruth's fifth-inning home run gives the Yankees a 3–1 lead, but Pittsburgh ties the game later. In the top of the ninth inning, Earle Combs walks, Mark Koenig beats out a bunt, and Ruth walks to fill the bases. Two outs later, a wild pitch rolls far enough away for Combs to score the winning run.
November 28 – Billy Evans quits as American League umpire to becomes business manager of the Cleveland Indians, following the purchase of the club by a group headed by Alva Bradley, to become the first General Manager in major league history. Evans, who worked as an AL umpire from 1906 to 1927, became, at age 22, the youngest umpire in major league history, and later became the youngest to officiate in the World Series at age 25.
March 4 – Horace Wilson, 84, American professor of English at Tokyo University during the modernization of Japan after the Meiji Restoration, who is credited with introducing baseball to Japan in either 1872 or 1873.
March 6 – John Tilley, 72, left fielder for the Cleveland Blues, Toledo BlueStockings and St. Paul WhiteCaps in parts of two seasons spanning 1882–1884.
March 16 – Jake Wells, 63, catcher and left fielder for the 1888 Detroit Wolverines and the 1890 St. Louis Browns.
March 27 – Joe Start, 84, prominent first baseman of the 1860s and 1870s.
October 4 – John Richter, 54, third baseman for the 1898 Louisville Colonels of the National League.
October 11 – Mike Corcoran, 69, pitcher in one game for the 1884 Chicago White Stockings of the National League.
October 14 – Ed Hughes, 47, pitcher for the Boston Americans of the American League in the 1905 and 1906 seasons.
October 22 – Ross Youngs, 30, Hall of Fame right fielder who hit a career .322 batting average for the New York Giants over 10 seasons from 1917 to 1926, which included four National League pennants and two World Series championships in 1921 and 1922.
October 25 – Tom Brown, 67, outfielder who played from 1892 through 1898 for nine teams in four different leagues, collecting 1951 hits in 1788 games, while managing two seasons for the 1897–1898 Washington Senators, and umpiring three full seasons.
November 7 – Ed Clark, 64, pitcher for the 1886 Philadelphia Athletics of the American Association,
November 8 – Phil Bedgood, 29, pitcher from 1922 to 1923 for the Cleveland Indians of the American League.
November 22 – John McGlone, 66, third baseman for the 1886 Washington Senators of the National League and the 1887-88 Cleveland Blues of the American Association.
November 30 – Jimmy Wood, 84, player/manager for the Chicago White Stockings, Troy Haymakers, Brooklyn Eckfords and Philadelphia White Stockings from 1871 to 1873, who hit .333 in 102 games and posted a 105–99 managerial record.