In an all-French match against the defending champion, Monfils did not face any break points -- hitting 34 winners to 17 for Gasquet, and serving nine aces to zero for his opponent.
"I had some back problems at the beginning of the week and I didn't know if I was going to be able to play, so to now be with the trophy is pretty crazy," Monfils told the ATP website. "I have been elevating my game match after match and I am extremely proud in the way I played today."
Monfils broke for a 4-3 lead when Gasquet's forehand sailed wide and the 30th-ranked Frenchman fired an ace to take the opening set.
He capitalized on another forehand error from Gasquet to break serve in the ninth game of the final set and clinched his first title of the season with a service winner.
"I need to congratulate Gael because he's played unbelievable all week," Gasquet said. "I wasn't able to read his serve, he was serving bullets all match. My only way out was to try to push him to a tie-break and wait for him to start making mistakes. But it didn't happen."
Monfils, who also won this tournament in 2010, improved to 6-4 against Gasquet.
A former top 10 player, Monfils struggled with a right knee injury in 2012 and dropped to 119th in the rankings last year.
He started the season with a runner-up finish at the Qatar Open in January, losing to top-ranked Rafael Nadal of Spain.