O’Sullivan had raced into an 8-3 lead but Trump managed to win four frames on the bounce to see him back to 8-7.
However, O’Sullivan regained his composure to defend his crown.
Trump made two century breaks over the course of the final but O’Sullivan was in imperious form as he rattled off four.
"I just played as well as I could," said O'Sullivan.
"I would like to say well done to Judd as he had a great tournament."