The small forward has started the team's last four games on the bench, which have all been won by the Celtics.
The 31-year-old told the team's website: "I'm having fun with it. It's a new point of my career. I'm kind of enjoying it, being able to give my most in a quick five, six-minute spurt and then turn it back over to the younger guys and let them play.
"I think I'm helping more from the sidelines, because you actually can see the game more and I'm able to talk to them, especially Jeff [Green] and [Jared Sullinger] and Kelly [Olynyk] and let those guys understand what they're doing out there on the court."
Wallace has averaged five points per game so far this season.