January 16 – Curt Flood, Gold Glove outfielder of the St. Louis Cardinals, files a civil lawsuit challenging Major League Baseball's reserve clause, a suit that will have historic implications. Flood refused to report to the Philadelphia Phillies after he was traded by the Cardinals three months ago, contending the baseball rule violates federal antitrust laws.
February 1 – The Hall of Fame Special Committee on Veterans selects former commissioner Ford Frick and former players Earle Combs and Jesse Haines for enshrinement.
February 19 – Commissioner Bowie Kuhn announces the suspension of Detroit Tigers pitcher Denny McLain, effective April 1, for McLain's alleged involvement in a bookmaking operation. The suspension will last three months; it was indefinite for a while before its length was set.
April 1 – The Milwaukee Brewers organization, headed by Bud Selig, purchases the Seattle Pilots franchise for $10,800,000. Although negotiations were conducted over a period of months, it was not until March 13 when a federal bankruptcy referee declared the Pilots bankrupt. Brewers tickets go on sale the next day. Team equipment is shipped to Milwaukee County Stadium, where the Pilots insignia is ripped off of the uniforms, since there is no time for new uniforms to be made.
April 7 – Major League Baseball returns to Wisconsin after a four-year absence as the Brewers play their first game in Milwaukee, losing to the California Angels 12–0 before a crowd of 37,237.
April 7 – Pitcher Dave McNally strikes out 13 in nine innings as the Baltimore Orioles rip the Indians, 8–2, on Opening Day at Cleveland Stadium. Paul Blair leads the offensive attack, driving in a pair of runs and scoring three times. McNally holds the Indians to two runs on four hits and three walks to get the win. Rookie Roy Foster belts a two-run home run to account for Cleveland's only runs.
April 22 – The New York Mets' Tom Seaver strikes out 19 San Diego Padres, including the last 10 in succession, in a 2–1 Mets win. Mike Corkins takes the loss. In this century, no one had ever struck out 10 in a row, a major league record. Counting the 10 whiffs, the Pads have struck out 29 times in two games, a National League record that will be topped in 1998 when the Houston Astros miss 31 times in two days. Jerry Grote adds one foul fly catch to his 19 putouts via strikeouts.
May 10 – Hoyt Wilhelm makes his 1,000th pitching appearance, the first pitcher in history to do so.
May 12 – At Chicago's Wrigley Field, Ernie Banks becomes the eighth member of the 500 home run club, connecting off Atlanta Braves pitcher Pat Jarvis during a 4–3, 11-inning Chicago Cubs win over the Braves. It is also his 1,600th career RBI. Ex-Cub Frank Secory umpires this game; he was one of the umpires in the 1953 game in which Banks hit his first home run. Billy Williams' homer in the ninth ties the game and Ron Santo's RBI single in the 11th wins it. Atlanta's Rico Carty, meanwhile, has three singles and has hit in 30 consecutive games.
May 17 – In the second game of a doubleheader against the Cincinnati Reds, Hank Aaron of the Atlanta Braves gets his 3,000th career hit, and is the founding member of the 3000-500 Club.
July 14 – At Riverfront Stadium, the National League wins its eighth straight All-Star Game, a thrilling 12-inning, 5–4 victory. Pete Rose crashes into Cleveland Indians catcher Ray Fosse to score the controversial winning run on Jim Hickman's single. Fosse, who never had the ball, hurts his right shoulder and is taken to the hospital. The game is scoreless until the sixth inning, with the NL limited to three hits in the first eight innings. In the ninth, the NL tees off on Catfish Hunter, driving in three runs to tie. Dick Dietz hits a leadoff home run in the inning. Claude Osteen pitches the 10th for the win, and Carl Yastrzemski of the Boston Red Sox captures the MVP trophy for the American League.