Babe Ruth had a streak of 7 years from 1926 to 1932.
Rusty Staub hit 6 home runs for the Houston Colt 45s in 1963 at the age of 19 and 2 home runs for the New York Mets in the 1984 and 1985 seasons at the age of 40 and 41.Gary Sheffield became the third player to accomplish this. He hit 4 home runs as a teenager with the Milwaukee Brewers and, through games played on May 1, 2009, 1 home run as a 40 year old with the New York Mets.
Darrell Evans hit 41 home runs with the 1973 Atlanta Braves (NL), and 40 home runs with the 1985 Detroit Tigers (AL). He was the first (I checked all players with 40 home run seasons before 1985).
For a season, no one. Through the 2008 season, the Mets have had three 40 home runs seasons: 1) Todd Hundley - 41 in 1996 2) Mike Piazza - 40 in 1999 3) Carlos Beltran - 41 in 2006 None of the three players listed above played for the Yankees. For a career, Darryl Strawberry hit 252 home runs for the Mets and 41 home runs for the Yankees.
Ty Cobb, who hit a home run in 1906, when he was 19, and smacked five home runs in 1927 when he was 40.
122 different players have had a total of 295 40-HR seasons.
Vinny Castilla with 3 ... he hit 40 home runs in both 1996 and 1997 and 46 home runs in 1998.
The Mets won 40 games in their first season in 1962.
Bartolo Colon is number 40 on the New York Mets.
Mickey Mantle hit career home run number 300 during his 10th season in the Major leagues, on July 4, 1960 batting right handed, at Griffith Stadium vs. the Wash. Senators off left handed pitcher Hal Woodeschick. It was Mantles 20th home run of the 1960 season when he hit 40.
He was 40 years old.
Aaron, Johnson , Evans