The 2-1 result now leaves Wigan - one of the pre-season favourites for promotion - six points adrift of safety, extending their miserable run to one win in 17 matches while the Millers won thier first game in 10.
Tom Lawrence scored the opener for Steve Evans' Rotherham after a dreadful mistake by Andrew Taylor.
Wigan levelled just after the hour mark when Ben Watson headed home James McClean's corner. But the visitors picked themselves off the canvas and regained the lead within a minute, Revell heading past Scott Carson from close range.
Credit must be given to the home side for the way they stuck at it, but they were denied a late leveller when Oriol Riera's header came back off the crossbar.
Wigan were first out of the blocks, and Callum McManaman skipped past three defenders before seeing his shot well saved by Adam Collin. A short corner by the home side presented Watson with a shooting opportunity, but his effort was deflected into the path of Emmerson Boyce, who could only head wide. Having soaked up a bit of pressure, the visitors then started showing themselves as an attacking threat.
Revell's shot was well parried by Carson, before Emmanuel Ledesma dragged his effort well wide of the mark. A poor backpass from James Perch almost let in Revell, with only smart footwork by Carson saving his side.
Watson should have opened the scoring for Wigan but blazed high and wide from inside the area. But Rotherham gradually took a hold on proceedings and started asking the more probing questions. Leon Barnett was at full stretch to cut out a cross from Ben Pringle, and it took a fabulous block from James Perch to snuff out a swift breakaway led by Lawrence and Ledesma.
Revell forced another save from Carson, before the Millers did take the lead five minutes before half-time. Taylor's error allowed Lawrence to run in on goal, and the young forward finished coolly past Carson.
Rotherham started the second half where they had left off in the first, and Barnett was again required to cut out the danger posed by Lawrence.
Wigan made a double change either side of the hour mark, throwing on strikers Marc-Antoine Fortune and Riera for Shaun Maloney and Don Cowie. And the home side found an equaliser within seconds of the second switch, McClean's corner being headed home by Watson at the near post.
With nearly 30 minutes to go, the home crowd urged their men on in search of a vital win at the foot of the table. But those plans were immediately nipped in the bud when the Millers regained the advantage within a minute. Barnett was penalised 30 yards from goal, and Ledesma's deep free-kick was nodded into the net by Revell.
Wigan's attempts at a second leveller were thwarted when Fortune fired over the top from a great position. And the home side knew the game was up when McManaman's cross from the right was headed against the bar by Riera in the closing stages.