The 20-year-old Canadian triumphed 6-2 4-6 6-3, but only after being a scare by the world number 64 at the WTA International clay-court event.
Pliskova was broken in her very first service game as Bouchard started strongly to wrap up the opening set before surging 4-2 ahead in the second.
Czech Republic's Pliskova – who beat top seed Angelique Kerber en route to the final – then clinched the next four games, including two breaks, to level the match.
The third and final set saw a total of five breaks of serve, but it was Bouchard who just about managed to keep her nerve, winning three games on Pliskova's service to break her WTA duck.
Bouchard said: "I'm really proud of myself. I worked really hard this week."
"This is kind of like a stepping stone for me. Winning a WTA title is of course a goal I've had, and I'm so happy to accomplish it, but I still want to achieve more - more titles, bigger titles."
Bouchard, who reached the semi-finals of the Australian Open earlier this year, is next in action against Israel's Shahar Peer in the first round of the French Open.