During a nervy opening in Belfast, Lisowski won the first frame on his sixth attempt with Trump responding with a break of 97 in the second before also winning the third.
After Lisowski won the fourth and Trump restored his one frame lead once again in the fifth, a century from Lisowski tied the match.
The 34-year-old was in a good position to move 4-3 clear, but called a foul on himself with Trump taking advantage and going ahead.
Lisowski then won the final frame before the interval to set up an exciting second session.
It continued to be a tight match after the break with Trump winning the opening frame, helped by a run of 82, and Lisowski levelling once again in the 10th.
The two friends continued to exchange frames until the 17th when, after both had chances to win, the Gloucestershire native won the frame to secure his first ranking event title.
