Tijjani Reijnders set up Pulisic's second-half equaliser before netting the winner himself in the 75th minute.
It was Pulisic's third goal in two matches, taking the US international to nine goals in Serie A and 15 in all competitions this campaign - equalling his tally from his first season at the club.
Milan moved up to seventh, five points below fourth-placed Juventus. Como remained seven points above the relegation zone.
Pulisic's two goals last weekend helped Milan fight back to win 3-2 at Lecce and end a three-match losing streak.
They again went behind on Saturday (Sunday AEDT), when Lucas Da Cunha drilled into the bottom left corner from the edge of the area in the 33rd minute.
Milan fans jeered loudly at halftime and it almost got worse for them four minutes after the restart, but Da Cunha's second goal of the night was ruled out for offside.
Instead it was Milan who levelled four minute later. Rafael Leao and Alex JimEnez combined on the left before picking out Reijnders, who delicately dinked the ball over the top for Pulisic to sweep into the far bottom corner from a tight angle.
Reijnders also clipped the top of the crossbar before scoring the winner in the 75th minute, slotting home after being sent through on goal by a backheeled pass by Tammy Abraham.
Como substitute Dele Alli's return to soccer lasted just nine minutes as he was shown a straight red card late on for a foul on Ruben Loftus-Cheek, shortly after coming off the bench for his first appearance in two years.
Elsewhere, Monza captain Armando Izzo scored his first goal in more than two years but it wasn't enough to secure a win as the last-placed team drew 1-1 against fellow strugglers Parma.
Izzo netted in the 60th minute, but Parma substitute Ange-Yoan Bonny levelled six minutes from time with a solo effort.
Monza remained 10 points from safety, while 17th-placed Parma inched three points clear of the relegation zone.
Hellas Verona moved seven points above the drop after a free kick by Ondrej Duda handed them a 1-0 win at Udinese, ending the hosts' six-match unbeaten streak.
Empoli were three points below Parma after losing 1-0 at Torino.
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