Midfielder Tommy Black pounced with an impressive double as Palace dragged themselves within sight of the play-offs.
The livewire 23-year-old set Palace up for the win with an early strike and rounded off the victory with an eye-catching 25-yarder as he sparkled in front of the TV cameras.
And it was pre-Christmas sickener for Rotherham after two away victories at Ipswich and Burnley.
Rotherham were caught cold when they pushed forward for a free-kick but when it was cleared to winger Andy Monkhouse he dithered and let in powerhouse Dele Adebola.
The Palace heavyweight brushed aside a double challenge from Paul Hurst and Chris Swailes and cut in an inviting low cross for Black to slot home from close in after 12 minutes.
John Mullin came close to levelling six minutes later when Alex Kolinko's punch from Rob Scott's long throw dropped kindly, but his stinging drive was cleared off the line by Darren Powell.
Adebola should have stretched the Palace lead after 26 minutes but hit a tame shot straight at keeper Mike Pollitt.
Palace struck again seconds before half time when Shaun Derry hit Rotherham on the break before angling a pass wide to Julian Gray who burst into the area and drilled his low shot past Pollitt.
Rotherham boss Ronnie Moore brought on pacy frontman Darren Byfield after the break and the home side pinned back Palace early on.
But 11 minutes after the restart it was Black who struck to put the game beyond the Yorkshire side.
Gray flashed down the left turning Rob Scott inside out before feeding Black who eased inside and unleashed an unstoppable shot that curled in from 25 yards.
And Palace were unlucky when Aki Riihilahti was harshly adjudged to have handled Richie BarkerÂ’s shot in the area.
Alan Lee's spot kick was parried by Kolinko, but Byfield pounced to drive home the rebound and give the Millers some consolation.