Bent, Villa's club record signing, was among the substitutes as Paul Lambert started with Gabriel Agbonlahor and Christian Benteke up front.
The England striker, with national manager and ex-Baggies boss Roy Hodgson watching from the stands at Villa Park, had only been on the pitch 11 minutes when he cancelled out Shane Long's opening goal.
Sunday's result left Villa two points clear of the bottom three.
Long missed a chance to give West Brom, who've lost just once in their first six league games this term, an early lead when he headed wide from close range.
But Villa worked their way back into the match and it needed a finger-tip save from Albion keeper Ben Foster to divert Brett Holman's long-range shot over the crossbar.
Foster then made another good save when he turned away a Holman shot that deflected off Billy Jones.
However, it was Villa who broke the deadlock in the 51st minute when Long turned in James Morrison's low cross for his fourth goal of the season.
Bent came on mid-way through the second half, in place of Benteke, and 10 minutes from time when the striker turned in a loose ball after Ciaran Clark's volley from Barry Bannan corner was blocked.
Albion almost won the match late on when substitute Roman Lukaku twice went close to regaining the lead for the Baggies.
First the striker, on loan from Premier League leaders Chelsea, saw a shot deflect off Clark onto a post and then saw another effort come off the legs of Villa keeper Brad Guzan.
Source: AFP
Source: AFP