Scottish international Miller fired a typical end-of-season game into life with a neat close range finish after 54 minutes before sealing the win in the last minute as Wolves extended their unbeaten run to 16 games.
His goals sent Rotherham crashing to a fourth successive defeat as they made another fruitless trip to Molineux.
Rotherham have not won a game at Wolves since the Second World War - losing seven and drawing three.
Wolves should have been well in control of affairs inside the opening ten minutes only to be let down by their finishing.
The ineffective Ki-Hyeon Seol, who paid for a dismal display by being taken off before half-time, should have scored after just four minutes.
But he sliced his shot from four yards into the sidenetting after a cross from Lee Naylor was deflected into his path by Miller.
Leon Clarke then volleyed a centre from Mark Kennedy over the bar in the ninth minute before Rotherham managed to work their way into the game.
Former Charlton forward Jamal Campbell-Ryce raced clear down the right wing in the 24th minute and cut inside Wolves central defender Jody Craddock before seeing his shot saved by Michael Oakes.
Skipper Chris Swailes then went close with a 33rd minute header after he rose high to meet a corner from Paul McLaren.
But that proved to be a rare spell of pressure for Rotherham whose fate was sealed after Wolves made a fast start to the second half.
Rohan Ricketts, who had replaced Seol, forced Gary Montgomery into a smart save in the 53rd minute before Wolves made the decisive breakthrough 60 seconds later.
Naylor sent over a left-wing corner that Mikkel Bischoff nodded down into the path of Miller, who stabbed the ball home from six yards.
Rotherham made a spirited bid to salvage something from the game only to see John Mullin denied twice.
First his 65th minute shot was blocked by Craddock before Oakes produced a superb one-handed save to turn away his header ten minutes later.
Miller then took advantage of the saves to help himself to a second goal in the fifth minute of injury time.
He raced on to a long through ball from Ricketts and beat Montgomery with an angled drive to give Wolves a somewhat flattering final scoreline.