Rotherham should have led at the break but squandered a string of chances and were kept at bay by Carlisle's stubborn defending.
But after the break it was a different story as the home side rattled in three goals in a one-sided encounter.
The Yorkshire outfit went ahead five minutes into the second half thanks to a goal from Andy Monkhouse in his first appearance of the season.
Monkhouse started the move before Chris Sedgwick, Nick Daws and John Mullin were involved.
And when the ball was cleared out it was Monkhouse who chested the ball down, broke into the area and then drove a left-foot shot past the keeper.
The home side could have been further in front but Ritchie Barker's impressive control and turn was rounded off by a shot over the bar.
In the 68th minute the home side added a second thanks to veteran striker Mark Robins.
Rob Scott aimed a deep cross to the far post, Barker headed back across and Mullins' goalbound header was blocked by the keeper but Robins pounced to head home the second goal.
Seven minutes from the end as Rotherham relaxed they paid the penalty.
A rare attack from Carlisle saw Brendan McGill making ground on the left before cutting inside and crashing his 25-yard shot past Mike Pollitt.
The goal gave Carlisle extra heart and they swept forward looking for an equaliser.
Rotherham responded well and added a third in the dying seconds.
Paul Warne, who had been on only four minutes as a substitute, made a surging run on the left before driving a superb shot past the keeper