The full-back netted twice in the first half and although the away side pulled one back through Cameron Howieson, the hosts were dominant for much of the match.
They were careless at times though and would have been pegged back were it not for Steven Thompson’s woeful penalty miss before Dean Shiels sealed victory late on.
Creating more than 20 chances, Rangers deserved their win but could have been more ruthless and still have things to work on as Mark Warburton’s rebuild starts gathering pace.
Nevertheless, their fans who made up the bulk of an excellent 49,216-strong crowd went home happy and having gone top of the league. They will now expect their team to stay there.
Rangers got off to the perfect start and went in front inside four minutes through their captain Wallace.
The visitors made a mess of clearing Barrie McKay’s corner and although Danny Wilson couldn’t convert, the skipper was there to lash high into the net from six yards.
While they were ahead early, Warburton’s men almost gifted their opponents a way back into the game through Wes Foderingham’s wayward pass.
But Scott Agnew, an Ibrox youth product, couldn’t capitalise and he wasted a free kick moments later when he aimed it straight at keeper Foderingham.
Rangers were tidy in possession and hit back positively, playing a high line and pressuring the Paisley team into giving up the ball on the occasions they had it.
After McKay volleyed over, they were soon two up as the lively winger found Jason Holt and his perfectly-weighted ball was threaded through for Wallace to slot home his second.
With that, Rangers followers would have forgiven for starting to consider how many more their team would score but St Mirren were quickly back in the game as they pulled a goal back.
Paul McMullan – on loan from Celtic – split the home defence and released New Zealand international Howieson and he drilled in from the edge of the area.
Martyn Waghorn came close to restoring the two-goal cushion with a fierce drive that arced just over and Holt forced a smart save from Mark Ridgers at his near post.
Tom Walsh also shot inches too high after a lovely flowing move that started with McKay tracking back well and Wallace bursting forward courtesy of a terrific flick.
Whereas Rangers should have been out of sight, St Mirren had a glorious chance to level after the break when James Tavernier fouled McMullan and a penalty was given.
But Thompson, a former Ibrox player, sent a poor effort high over the crossbar and that was a real let-off for the hosts after they had switched off in defence once again.
The title favourites set about trying to kill the game off but nobody could poke in Waghorn’s teasing cross in, substitute Nicky Clark was denied then Waghorn nodded just wide.
Tavernier bent a free kick a yard over, Waghorn curled past after being set up by his former Wigan team-mate and Ridgers saved when a Clark header seemed set to go in.
St Mirren’s resistance could only carry on for so long and Rangers finally got their clincher a minute from the end when Shiels made it 3-1.
Waghorn’s excellent reverse pass freed David Templeton, he crossed to his fellow substitute and although Ridgers stopped him initially, he forced the rebound over the line.