Ibrahimovic, back from a two-game suspension, created goals for Maxwell and Blaise Matuidi either side of halftime before rounding off the scoring in the 70th and 89th minutes.
PSG, who had not won for three league matches, have 26 points from 14 games and lead second-placed Saint-Etienne, who lost 1-0 at Valenciennes on Friday, by a point after reaching the Champions League last 16 on Wednesday.
PSG struggled at times against second-bottom Troyes, with Ibrahimovic's return making all the difference.
"It takes more than two defeats to put pressure on me. We're here to win. It was important to send a message," Ibrahimovic told reporters.
"This week, the team had a good reaction. We scored six goals, did not concede," said coach Carlo Ancelotti, also referring to PSG's 2-0 win at Dynamo Kiev in the Champions League.
Ezequiel Lavezzi came close to scoring on the half-hour, but Yohann Thuram-Ulien pulled off a fine save to parry the Argentine's header away.
With 20 minutes to go, Ibrahimovic scored a carbon copy of Matuidi's goal from Nene's pass.
Elsewhere, Nancy's winless streak stretched to 14 games in all competitions after an Adrian Mutu penalty gave AC Ajaccio a 1-1 comeback draw at Marcel Picot.
