A first-half opener from Mark Hudson followed by leading scorer Reuben Reid's ninth of the season was enough to see off Macclesfield.
Rotherham were hoping to bounce back after a string of away defeats and came close to an opener after five minutes.
A free-kick from Hudson was aimed for Ian Sharps who nodded across goal and a Reid header went over.
But seven minutes later it was Hudson who made the breakthrough when he clipped a first-time shot past Jonny Brain after Reid drove in a low cross from the right .
In the 16th minute Alex Rhodes curled in a dangerous corner and Sharps stooped to head but hit effort drifted over the top.
Macclesfield responded with a lively spell that had the home side back-pedalling but, when Jamie Tolley threatened, Jason Taylor stuck out a foot and conceded a corner.
It triggered more pressure from the visitors and as they looked for an equaliser, Tolley raced in but angled his shot on the run wide of Andy Warrington's goal.
Just before the break, Rotherham might have stretched their lead after a sweeping move that saw Jamie Green cross, Reid headed down but this time Hudson smashed his shot over.
Ten minutes into the second half Tolley was in a good position to punish Rotherham's sloppy defending ten yards out but ended up clutching his head in frustration after completely mis-hitting his shot.
Macclesfield sub Tom Elliott gave the visitors fresh hope as they pushed for an equaliser but he fired wide from the right.
But after 76 minutes Rotherham put the game beyond the visitors when Drewe Broughton headed on and Reid lifted a clever ball over the keeper for the second.