It was a third career title on the main tour for the 24-year-old, following victories four seasons ago in Hamburg and Naples, and brought an end to a seven-match losing streak in tournament showpieces.
In a dominant 81-minute performance in southeast France, Musetti secured two breaks of serve early in each set and forced his second-seeded opponent into 28 unforced errors.
The routine victory stood in juxtaposition to Musetti's grinding route to the final, in which the sixth seed had to show great physical resilience to beat France's Luca Van Assche in a three-and-a-half-hour marathon in the quarter-finals, as well as a lengthy last-four success against his compatriot Fabio Cobolli in which he saved four match points.
"The spirit of fight was the key for this tournament," Musetti said.
"I had an incredible attitude. I have to say thanks to my team... Today I felt more relaxed inside my head and my tennis was more fluid and it was a great performance.
"It is such a dream I don't want to wake up."