The Blades had trailed in the first half to a Kevin Lisbie strike before equalising just before the break through Lee Williamson.
Danny Wilson’s side then pushed on to seal the points courtesy of Evans and Doyle to edge a step closer to the Championship.
And with Wednesday being held to a 1-1 draw at Colchester United, United now enjoy a four point advantage over their Steel City rivals with just three games to go.
The all-important breakthrough came nine minutes into the second half courtesy of a decent move that saw Ched Evans lay a pass from Kevin McDonald into the path of Doyle, who curled an exquisite shot beyond Jamie Jones and into the net.
United’s afternoon then improved further when Orient were reduced to ten men following a wild challenge on Lee Williamson that saw Ryan Dickson shown a straight red card.
Danny Wilson’s side then wasted several chances to put the game to bed as Evans had a shot blocked and Chris Porter had a shot turned round the post by Jones.
Evans then rounded off the afternoon with a trademark finish after latching on to Ryan Flynn’s pass and edge United closer to promotion.