Giacomo Bonaventura has given AC Milan the lead going into half time, as he curled in his free kick from just outside the area minutes before the break.
Oscar Hiljemark cancelled out Carlos Bacca's opener as the game looked to be heading for a draw going into half time.
Milan were almost gifted a goal in the opening few minutes, after Palermo defender Aljaz Struna nearly made the mistake of putting the ball into his own net.
However, the Rossoneri were dealt a blow midway through the first half, as full-back Ignazio Abate was forced off with an injury.
Despite enduring the disappointment of seeing their first-choice right-back go off, it was Sinisa Mihajlovic's side that took the lead through a well-worked team goal as Giacomo Bonaventura back-heeled into Bacca, who smartly finished with one touch into the roof of the net, making it 1-0.
However, Milan's lead lasted only 10 minutes as Hijemark managed to connect with Robin Quaison's corner, as the Swedish midfielder dived backwards to head past the helpless Diego Lopez.
The host's lead was restored five minutes before the break, as Bonaventura curled a free kick into the top left-hand corner.