April 1 – Starting off with a bang, Japanese star Sadaharu Oh hits a grand slam home run on opening day. It is his 757th home run.
April 13 – The New York Yankees defeat the Chicago White Sox 4–2 in their home opener on Reggie Candy Bar Day. Reggie Jackson slugs a 3-run home run in the first inning, and the field is showered with candy bars which were given out free to the fans at the game.
April 20 – With two out in the top of the fourth inning, the Atlanta Braves' Jeff Burroughs hits a ground ball up the middle that San Diego Padres rookie shortstopOzzie Smith dives for behind second base. As he was in the air, the ball hits the base, and caromes behind Smith. As he is diving in the opposite direction, Smith reaches out with his bare hand and catches the ball. He bounces up, and throws Burroughs out at first. The Padres win the game 2–0.
May 14 – With the Chicago Cubs losing 7–5 to the Los Angeles Dodgers, Dave Kingman hits a two run home run with two outs in the ninth inning to send the game into extra innings. Kingman, who had also homered in the sixth, hits his third home run of the day in the fifteenth inning to give the Cubs a 10–7 victory over the Dodgers at Dodger Stadium, and end his day with eight RBIs. Following the game, Paul Olden, a reporter for radio station KLAC in Los Angeles asks Dodgers manager Tommy Lasorda, "What's your opinion of Kingman's performance?" during his post-game interview. Lasorda goes off in a now-famous obscenity-laced tirade.
June 16 – In his 12th major league season speckled with near-misses, Cincinnati's Tom Seaver finally hurls a no-hitter. The Cardinals are the 4–0 victims as Seaver strikes out 3 batters.
June 17 – The Yankees' Ron Guidry strikes out 18 batters — 15 in 6 innings — in a 4–0 shutout of the California Angels, setting an American League record for left-handers. The victory raises the New York Yankee southpaw's record to 11–0.
July 13 – Jerry Koosman and Tom Seaver lock up for the second time since Seaver's trade to the Cincinnati Reds. Koosman and the Mets beat Seaver and the Reds, 4–2. Only one of the three runs Seaver gives up is earned.
July 17 – The Kansas City Royals defeated the New York Yankees 9-7 in 11 innings, but the game is remembered for Reggie Jackson ignoring signs from third-base coach Dick Howser with the score tied 5-5 in the bottom of the 10th. With Thurman Munson on first, manager Billy Martin wanted Jackson to sacrifice bunt. Jackson made a half-hearted attempt with the first pitch, and Martin removed the bunt sign. Jackson, however, defied Martin and still attempted a bunt, but ended up striking out. Jackson was suspended by Martin for five games.
As Reggie Jackson was returning from suspension, Billy Martin says in a post-game interview about Jackson and Yankee owner George Steinbrenner, "One's a born liar (referring to Jackson), and the other's convicted (referring to Steinbrenner, about an incident from the past when Steinbrenner was accused of making illegal presidential campaign contributions)." Martin later appears on live television tearfully announcing his resignation from the Yankees, although some sources believed Steinbrenner actually fired him. Bob Lemon is named Yankee manager for the remainder of the season.
September 14 – 39-year-old Atlanta Braves pitcher Jim Bouton earns his 62nd and final big league victory (his first since 1970), a 4–1 win over the San Francisco Giants. Bouton is best known as the author of the baseball diary Ball Four.
September 23 - Following a dinner party in Gary, Indiana, California Angels outfielder Lyman Bostock was killed while riding in a car with several others. The estranged husband of a woman in the car fired a single shotgun blast into the car, killing Bostock. Bostock was 27 years old.
November 28 – The Cincinnati Reds dismiss their nine-year manager, Sparky Anderson, who had led the team to five NL Division titles, four NL Championship pennants, two World Championships (1975–76), and averaged 96 wins per season. Anderson will become the manager of the Detroit Tigers in 1979, replacing Les Moss.
January 7 – George H. Burns, 84, first baseman for five AL teams who batted .307 lifetime and won 1926 MVP award with the Cleveland Indians
January 13 – Bill Clowers, 79, pitcher for the Boston Red Sox in the 1920s
January 13 – Merwin Jacobson, 83, backup outfielder for the New York Giants, Chicago Cubs and Brooklyn Robins between 1915 and 1927
January 13 – Joe McCarthy, 90, Hall of Fame manager who led the New York Yankees to eight pennants and record seven World Series titles; also won 1929 NL pennant with Chicago Cubs, and was first manager to capture titles in both leagues; 2125 career wins ranked 4th in major league history, and winning percentages of .615 (regular season) and .698 (postseason) were both records
January 27 – Monte Pearson, 69, All-Star pitcher who won 100 games, mainly with the Indians and Yankees
February 3 – Mike Herrera, 80, second baseman for the Boston Red Sox from 1925–26, and one of the first men to play in both the major leagues and the negro leagues
February 23 – Vic Harris, 72, outfielder and manager in the Negro Leagues who guided the Homestead Grays to seven Negro National League pennants, including five in a row from 1937 to 1941; played in six East-West All-Star games between 1933 and 1947
March 12 – Gene Moore, 68, All-Star right fielder known for his accurate arm
March 21 – Fritz Coumbe, 88, a pitcher for the Boston Red Sox, Cleveland Naps & Indians, and Cincinnati Reds between 1914 and 1921
March 30 – Billy Cox, 58, third baseman, mainly with the Brooklyn Dodgers, known for spectacular defense
April 8 – Ford Frick, 83, Hall of Fame executive who served as commissioner from 1951 to 1965 and NL president from 1935 to 1951; served as ghostwriter for Babe Ruth while a sportswriter, and in 1961 ruled that home run records of Ruth and Roger Maris would be recorded separately based on season length
April 14 – Joe Gordon, 63, 9-time All-Star second baseman in 11 seasons for the New York Yankees and Cleveland Indians who won the 1942 MVP award; set AL record of 246 home runs at his position, later a manager and scout
April 15 – Nick Cullop, 78, outfielder for the New York Yankees, Washington Senators, Cleveland Indians, Brooklyn Robins and Cincinnati Reds, and also a longtime player/manager at minor league level
April 20 – Jack Graney, 91, Canadian left fielder and leadoff hitter for the Cleveland Indians who led AL in walks twice and doubles once; was first batter ever to face Babe Ruth, and later became broadcaster
May 29 – Carl Reynolds, 75, outfielder for five teams who batted .302 lifetime