Yankees who were another team's season home run king.

Through 2018 current and former Yankees who held another team's season home run record while playing for the Yankees.

Granderson, Beltran and continuity v. winning.  Monday, December 9, 2013

The Yankees now have the Met home run king and the Mets have a Yankee who both equaled and exceeded the Met record.
_____________________________________

Giancarlo Stanton Miami 59
Alex Rodriguez Texas 57

Alfonso Soriano Washington (formerly Montreal) 46

Carlos Beltran Mets 41; will play for the Yanks in 2014
Babe Ruth 29 Red Sox

Johnny Mize 51 Giants and 43 Cardinals

Andrew Jones 51 Braves
Gary Sheffield 42 Marlins
Jesse Barfield 40 Blue Jays
Reggie Jackson 39 Angels
Charlie Hayes 25 Rockies
Jim Wynn 37 Astros
Steve Balboni Royals 36; returned to Yanks for his final two seasons
Darryl Strawberry Mets 39; held Met record 1988-1995.  Strawberry played with the Yankees 1995-1999.  Todd Hundley broke Strawberry's record in 1996 with 41, which Beltran later tied.  Immediately preceding Strawberry it appears that ...

Dave Kingman held the Met record starting in 1975 with 36, then 37 twice, the second after returning to the Mets in 1982 leading the old National League.  Kingman played briefly for the Yankees in 1977.

So, three players who previously held the season home run record for the Mets will have subsequently played for the Yankees.

If I missed someone, please let me know.  Check it out for the team you root for.