OK, so you already know that the most home runs in a major league game by one player is four. Sixteen players have done it, most recently Josh Hamilton in 2012 for the Texas Rangers.
Other articles under this heading have detailed each four-homer performance sufficiently. Here, I'll provide some interesting additional facts for a few of those events, and also describe some four-homer oddities which don't have the status of a "record" because they didn't happen in one game, or in the regular season. Finally, there's the short list of players who have hit more than four homers in one day!
Let's start with third baseman Bob Horner, of the Atlanta Braves, who blasted four homers against the Montreal Expos on July 6, 1986. Unfortunately for the Braves, the Expos won, giving Horner the distinction of being the only player in the 20th century to homer four times in a game his team lost. Ouch!
Rocky Colavito, whose family came to New York from the same Italian town as my mother's father, and who shares his name with my great-grandfather, my mother's brother and many of our cousins, knocked out four long ones for the Cleveland Indians on June 10, 1959, at Baltimore's late, great Memorial Stadium. It meant nothing to me at the time. I was just six years old and wasn't the least interested in baseball. it means more now because of the Italian connection, and because Memorial is where my hometown team, the Mets, won their first World Series game in 1969. I was fortunate to attend several games at Memorial in the late '80s when I was stationed near Baltimore, so that closed the circle for me. Renowned for his fabulous throwing arm, Colavito is unique among the 16, because he also made two pitching appearances in the big leagues, earning a victory in relief for the Yankees in 1968, his final season.
"Hard-hittin' " Mark Whiten did the deed on September 7, 1993 for the Saint Louis Cardinals. What makes Whiten's feat special was that he also tied the major-league record for RBI in one game, 12, which is much more rare than the home-run feat, having been achieved only once before, by "Sunny" Jim Bottomley, also of the Cardinals.
Although he didn't hit four home runs in a single game, Reggie Jackson owns a four-homer quirk: He hit the final three pitches he saw in the 1977 World Series for home runs, then homered on the first pitch he saw in the 1978 regular season. I'm pretty sure he's the only player in major-league history to be able to lay claim to such a feat.
Art Shamsky of the Cincinnati Reds preceded Jackson by hitting four homers in four consecutive at-bats over two games in a strange way. In 1966, Shamsky entered a game as a pinch-hitter in the 9th inning and homered. The game went extra innings, long enough for Shamsky to get two more at-bats. He homered each time, then, two days later, homered in his first at-bat.
Of the eleven most recent players to hit four home runs in a game, five of them (Gil Hodges, Willie Mays, Mike Cameron, Shawn Green and Carlos Delgado) played for the Mets AFTER accomplishing the feat for another team. Shamsky was also a huge part of the Mets first successful season, their championship 1969 campaign.
Green and Cameron had their four-homer games in 2002, the only time it has happened more than once in a season.
Four is not the big-league record for most homers in one day by one player. It's five, and it's happened twice.
Stan "The Man" Musial did it first, on May 2, 1954 in a double-header against the New York Giants.
Then, on August 1, 1972, Nate Colbert of the San Diego Padres had a career day by hitting five homers and driving in 13 runs in a double-header against Atlanta. For some guys who come off the bench, that would be a decent season! In an incredible coincidence, Colbert is a native of St. Louis and says he was in the stands at Sportsmen's Park on Musial's five-homer day. Wow!
Gotta love the long ball!