Substitute Ryan Hall was the hero for Millers, who went up via the play-offs, stabbing the ball home in the 76th minute after Carl Ikeme had palmed away Craig Morgan’s powerful header from Ben Pringle’s corner.
Hall, however, was injured in the process and had to be replaced by Kieran Agard, who had refused personal terms after the Millers had agreed an £850,000 fee with Leeds on Friday.
Wolves were left to rue missing a succession of first-half opportunities - Adam Collin producing great reflex saves in quick succession from Bakary Sako - although new Millers loan signing Paul Taylor had clipped the bar on his debut.
“Ryan will be fine. He’s a terrific talent and if you get him solely focused on his football then he’s got a sweet left peg and he can see passes,” said Millers boss Steve Evans.
“He’s got a real hunger and desire to make a point here and we’re delighted to get him here. I hope he enjoys his evening in a moderate way because we’re training again tomorrow.
“I thought he showed a great desire and he gets the luck that comes with that and the goal. We are fortunate that the ball rolls into the net.
“I think today we’ve not been right in the first half, we’ve had to change little bits at half-time and have a little bit more desire to win a football match and we’ve displayed that in the second half.
“The goal came from Ryan showing that type of desire and we have got a great win.”