Evans returns after relegated Rotherham sack manager Richardson
Richardson succeeded Matt Taylor in December but presided over a woeful run, losing 18 of his 24 games in charge and overseeing Rotherham's demotion from the Championship to League One.
Just hours after announcing Richardson's exit, Stevenage manager Evans was named as his replacement on a three-year deal.
Evans previously managed Rotherham from 2012-15, when he guided the Millers from League Two to Championship safety. He leaves Stevenage having taken them from the bottom of the fourth tier to the verge of the League One play-offs.
Rotherham chairman Tony Stewart said: "On behalf of everyone at Rotherham United, I'm absolutely delighted to welcome Steve Evans and Paul Raynor back to the football club.
"Leam and Rob's (Kelly, assistant manager) departure was not something we took lightly, but following extensive conversations at board level, it was unanimously agreed that a change of direction was needed to give us the best possible chance of bouncing back to the Sky Bet Championship at the first time of asking.
"In Steve and Paul, we have two individuals that understand the Rotherham United 'DNA' and know what it takes to build a successful team. They have a proven track record of success at a plethora of clubs, including our own."
