The former Stoke striker netted with a downward header in the seventh minute and a low near post shot after 38 minutes as Vale failed to defend two Oliver Norburn corners from the right,
The visitors spurned early chances when Sam Morsy and Chris Birchall volleyed over, but always looked suspect at the back.
Brunt had a great second-half chance to complete his hat-trick, but shot over an open goal after Lee Brown's effort had been parried by Vale goalkeeper Chris Neal.
Tom Pope headed wide for Vale in the second half, but Rovers held out comfortably,
A bad night for the visitors got worse when substitute Ashley Vincent was stretchered off 10 minutes from time with what appeared a serious leg injury.
Rovers' victory moved them into mid-table and continued the remarkable revival since John Ward was appointed manager in December.