Posted By:
Fred CTed,
I guess it seems that Patsy Tebeau and Mike Griffin don't count. Both homered in their first at bats. Oddly enough both did it on April 16, 1887. I'm not sure whose team played first that day so I'm not sure which player is credited as the first player to do it.
What is the answer that you had in mind?
Edited to add: I see John already provided the same answer above.