Polo grounds
Daniel Sepic of Pennsylvania hit the first ever home run.
Babe Ruth hit his first home run in 1915. As he was born in 1895, he would be 20 years old when he hit his first home run.
I
The first home run at PNC Park was hit by Sean Casey of the Cincinnati Reds. The first Pirates Homerun was hit by John Vander Wal.
Babe Ruth hit his first home run in 1915 with the Boston Red Sox.
Mulder was the first pitcher to hit a home run at the new Busch stadium!
Dolph Camilli hit the first ever televised home run as the Dodgers beat the Reds 6-1.
Travis Lee (who???) hit the first home run in the first regular season home game played on March 31, 1998
No, he hit a walk off home run in his first major league game but it was not his first at-bat.
Run It
On April 10, 1971, Don Money of the Philadelphia Phillies hit the first home run in Veterans Stadium.
Not in MLB ... although he did hit his first MLB home run in his 3rd ever at bat ... it was a grand slam.