Brandon Jennings, Samuel Dalembert and Mike Dunleavy each scored 13 points for the Bucks (2-1), who shot 41.9 percent from the field. Rookie John Henson exited with a left knee injury and did not return.
The Bucks pulled to 94-91 after a 14-4 run capped by Beno Udrih's two free throws with 3:02 left.
Robinson responded with a jumper, and Hamilton and Carlos Boozer each hit two free throws to put the game away.
Milwaukee pulled within six in the third quarter, but the Bulls answered with a 13-3 run for a 79-63 lead.
The Bulls last trailed 30-29 late in the first quarter, but Robinson hit a 35-footer before the buzzer to give Chicago the lead for good.
Nazr Mohammed scored eight points during the Bulls' 17-2 run to open the second quarter, extending Chicago's lead to 49-32.