Scunthorpe made the much brighter start in front of a sparse crowd at Don Valley and the League One side scored with their first attack after Kevan Hurst's corner found Milne unmarked on the penalty spot and the central defender had no problems in finding the top corner.
The Iron continued to dominate the game and went close when new striker Gary Hooper had a looping volley that went just wide. The Millers were finding it difficult to establish themselves with trialist Drew Broughton struggling to link up with Ryan Taylor.
However, it was Taylor that had the Millers' first chance when he drilled a shot from 18 yards just wide. Mark Robins' men gradually began to assert themselves and went even closer to levelling when Antiguan international Marc Joseph curled a 30-yard free-kick just wide.
Scunthorpe nearly doubled their lead just before the break when Peter Winn cut inside from the left-hand side and curled a shot on to the crossbar with Cann left helpless.
The Millers were unchanged for the second half and made a much better start but it was once again the visitors that struck the woodwork when Hooper headed on to the bar from 12-yards out.
It was a lucky escape for the Millers and as they introduced Rueben Reid, they began to dominate. A long ball was knocked down by Broughton to Cummins but his half-volley on the edge of the area flew just over the bar.
With the pacey Reid beggining to take effect the game opened up and Scunthorpe once again missed the chance to extend their lead when Ian Morris blazed over from 4 yards with the goal at his mercy.
Morris was left to rue the miss as Rueben Reid fired the Millers level on the 67th minute with a fine goal. A long kick from Cann in the Rotherham goal fell to Reid on the edge of the area. He hit a delightful first time left-footed shot that sailed in to the top corner of the goal.
The home side had deserved the goal and were now rampant. With
Broughton exiting to make way for a front three of Reid, Rhodes and Taylor, Rotherham were totally on top and Reid caused more trouble when his dribble and 20-yard shot was fired just wide.
As the game looked to be petering out for a draw the Millers stole the victory with a nice goal. Reid and Green combined down the left and Green whipped in a wicked ball that fell to Ryan Taylor at the back post. He contolled the ball neatly before blasting the ball past Lillis in the Scunthorpe net to give Rotherham a late victory.