Rafael Leao had given the Rossoneri the lead just after half-time before Ibrahimovic, starting for the first time since his return, doubled their advantage with a left-footed strike.
The former LA Galaxy and Sweden striker had another goal ruled out for offside.
“I’ll celebrate like a God at San Siro, not here,” Ibrahimovic said.
“The important thing is that I feel good. I missed a few balls at the beginning of the game, but I need to play games to get back in shape.”
Ibrahimovic, 38, signed a six-month deal at the Serie A side in December, with the option of another season.
He scored 42 goals in 61 league games for the club between 2010 and 2012. His strike on Saturday was his 57th goal for Milan and 123rd in Serie A, having also played for Inter Milan and Juventus.
“I feel good, the coach just wanted to think about my age and see if I needed a rest, but there’s no problem” added Ibrahimovic.
“My brain is always the same and the body has to follow.”
It was AC Milan’s first win since early December and they move to within four points of sixth-placed Cagliari who occupy the league’s final Europa League spot.