January 24 – The New York Mets are sold to a group headed by Nelson Doubleday, Jr. and Fred Wilpon for an estimated $21.1 million. It was, at the time, the highest amount ever paid for an American professional sports franchise.
February 12 – The Board of the Oakland Coliseum and the Oakland City Council both reject an attempt to buy out the remainder of the Oakland Athletics' lease to the stadium. This blocks an attempt to sell the team and a possible move to Denver.
March 12 – Slugger Chuck Klein and former Boston Red Sox owner Tom Yawkey are elected to the Hall of Fame by the Special Veterans Committee. Yawkey is the first club owner selected who never served as a player, manager or general manager.
Houston Astros pitcher Nolan Ryan strikes out César Gerónimo of the Cincinnati Reds, to become the fourth major league pitcher ever to reach 3,000 career strikeouts. Gerónimo was also Bob Gibson's 3,000th career strikeout victim six years earlier. Despite the milestone, Ryan allows six runs in 4.1 innings and Houston loses, 8–1.
September 24 – The Atlanta Braves reach the 1,000,000 mark in attendance. It marks the first time that every National League team has drawn at least 1,000,000 fans for a season.
October 4 – In a 17–1 rout of the Minnesota Twins, Willie Wilson of the Kansas City Royals becomes the first major league player ever to be credited with 700 at-bats in a single season, and ends the year with 705 at bats. He also sets the AL record for singles in a season with 184, eclipsing the mark Sam Rice set in 1925. Wilson also becomes only the second player in major league history to collect 100 hits from each side of the plate, matching the feat accomplished by Garry Templeton in 1979.
October 4 – Philadelphia's Mike Schmidt hits a 2-run home run in the top of the 11th inning to give the Phillies a 6–4 win over the Montreal Expos at Olympic Stadium, clinching the National League East title. The home run is Schmidt's 48th of the season, breaking Eddie Mathews' single-season record for third basemen set in 1953.
October 9 - The Kansas City Royals win Game 2 of the 1980 ALCS 3-2, but the game is remembered for the top of the eighth inning. With Willie Randolph on first with two outs, Bob Watson lines a double to left. Yankee third base coach Mike Ferraro waves Randolph home, and the Royals gun him down at the plate. With a national television audience looking on, Yankee owner George Steinbrenner is shown in the stands on ABC game cameras shouting Ferraro's name at general manager Gene Michael. Steinbrenner ordered Yankee manager Dick Howser to fire Ferraro on the spot right after the game, but Howser refused.
October 21 – The Philadelphia Phillies win the World Series, the first WS Championship in their 98-year history, by beating the Kansas City Royals, 4–1, in Game Six. Steve Carlton earns the win, though the most memorable moment may be Tug McGraw on the mound jumping for joy as he earns the save after loading the bases with no outs. Another equally memorable moment comes with one out in the bottom of the ninth when Frank White's pop-up is bobbled by Bob Boone, only to be tipped into the glove of Pete Rose. Philadelphia's Mike Schmidt is named MVP, hitting .381 with two home runs and seven RBI, while KC's Willie Wilson is the "goat", striking out a WS-record 12 times, including the final out of the Series with the bases loaded, and hitting only .154. Of the original 16 Major League franchises from 1901, the Phillies are the last to win their first World Series.
January 10 – Hughie Critz, 79, second baseman for the Cincinnati Reds and New York Giants who led NL in fielding four times and double plays three times.
January 21 – Gene Rye, 73, outfielder for the 1931 Boston Red Sox.
February 1 – Fred Walters, 67, catcher for the 1945 Boston Red Sox, and one of many players who only appeared in the majors during World War II.
February 2 – Jack Rothrock, 74, center fielder for four different teams from 1925 to 1937, who led the victorious St. Louis Cardinals with six RBI in the 1934 World Series.
March 1 – Emmett Ashford, 65, the major leagues' first black umpire, who worked in the American League from 1966 to 1970 and in the 1970 World Series.
March 1 – Johnny Watwood, 74, center fielder who played from 1929 to 1939 for the Chicago White Sox, Boston Red Sox and Philadelphia Phillies.
April 7 – Buck Canel, 74, Spanish-language broadcaster of 42 World Series, as well as many years of New York Yankees games.
April 21 – Ray Dobens, 73, pitcher for the 1929 Boston Red Sox.
April 21 – Joe Page, 62, All-Star relief pitcher for the New York Yankees who set single-season record with 27 saves in 1949, led AL in saves and appearances twice each.
April 28 – Bob Porterfield, 56, All-Star pitcher who was named The Sporting News AL Pitcher of the Year in 1953 after a 22–10 season with the Senators.
June 1 – Rube Marquard, 93, Hall of Fame pitcher who retired with 201 wins and the NL record for career strikeouts by a left-hander (1593); had 19 consecutive wins for the Giants in 1912 for a modern major league record.
June 3 – Fred Lieb, 92, sportswriter who covered every World Series from 1911 to 1958.
June 9 – Odell Hale, 71, infielder for the Cleveland Indians in the 1930s, who hit .300 three times and collected two 100-RBI seasons.
July 4 – Jack Martin, 93, shortstop who played from 1912 to 1914 for the New York Highlanders, Boston Braves and Philadelphia Phillies.
July 23 – Wally Snell, 91, catcher for the 1913 Boston Red Sox, who later went on to a distinguished career as a college botany professor and athletic coach at Brown University for four decades.
July 30 – Joe Lucey, 83, infielder/pitcher for the New York Yankees and Boston Red Sox between 1920 and 1925.