Final answer:
Alex Rodriguez broke Lou Gehrig's record for the most career grand slams after 75 years. He played on the same team as Gehrig, the New York Yankees.
Step-by-step explanation:
The player who broke Lou Gehrig's record for the most career grand slams after 75 years was Alex Rodriguez. He played on the same team as Lou Gehrig, which is the New York Yankees. On June 12, 2012, Rodriguez hit his 24th career grand slam, surpassing Gehrig's record. This achievement solidified Rodriguez's place in baseball history.
On August 20, 1938, Lou Gehrig hit his 23rd career grand slam for the New York Yankees, setting a record that stood for 75 years. This record was eventually broken by Alex Rodriguez, who, like Gehrig, played for the Yankees. Rodriguez hit his 24th career grand slam on September 20, 2013, surpassing Gehrig's long-standing record.