Tammy Abraham put Villa ahead with a 27th-minute goal on his home debut but they had to wait until the 83rd minute before Anwar El Ghazi killed the game off.
Unfortunately for a battling Rotherham side, who have given a good account of themselves upon their return to the Championship, they slipped to a 26th reverse in their last 28 away games in this division.
Rotherham manager Paul Warne expressed his disappointment with the result but said: “I am really proud of the way team are playing.
“They were shattered at the end and criticised themselves afterwards and thought they deserved a draw.
“The second goal took off all the pressure but the lads have to take some confidence from this game.
“They have earned the right to play at these great stadiums and I didn’t think they let themselves down against Villa.”
Warne admits that it would be good to win away from home having lost 26 of their last 28 Championship games.
“We are doing everything we can to win away,” said Warne. “Hopefully it will come sooner than later.”
Villa came out of the blocks in a positive fashion to put immediate pressure on the Millers but their finishing power was lacking. Twice in quick succession goalkeeper Marek Rodak was the right place at the right time to keep out efforts from Conor Hourihane and Jonathan Kodjia.
On the back of their 1-0 home win over Derby, the Millers were surprisingly quick to counter-attack and were far from over-awed by their opposition, exemplified when Richie Towell played a neat one-two and watched his low shot whistle narrowly wide.
Despite their limited resources Rotherham were highly competitive and gallantly defied Villa until the 27th minute when Jack Grealish’s astute pass put Kodjia in possession who found Abraham to notch a simple tap-in goal.
As Villa strived to find some finishing power they had an escape when Jon Taylor failed to convert a Zak Vyner cross.
But the game was put out of Rotherham’s reach when El Ghazi converted a high right-wing cross from Ahmed Elmohamady.