"Goals bring confidence and just playing games does as well," he told BBC Newcastle.
"I always thought if I had a few games in the team I'd get stronger."
Despite being signed as a striker, Campbell's recent first-team outings have been in an unfamiliar role on the right of the midfield, a role which the former England under-21 forward says is growing on him.
"I don't mind playing out there on the wing," Campbell added.
"Obviously I'm a striker, but I have enjoyed myself over the last couple of games and I don't mind playing there."
Sunderland boss Bruce signed Campbell from Manchester United in July 2009 for £3.5m, and the Huddersfield-born striker has since made 27 appearances, scoring four goals.