The 28-year-old American won the fight on a technical knockout in the 10th round after knocking down his compatriot three times.
"I love to win, finishing guys is the last piece of the puzzle," said Ward.
"Against better competition, I rise to the occasion. I don't know what's next after that.
"A move to light-heavyweight at some point is not out of the question."
Saturday's fight was held in Ward's hometown of Oakland.