Francis Dickoh scored Hibs’ first away goal of the year to move his team six points clear of the hosts.
After a troubled start to his tenure, this was manager Colin Calderwood’s third league win on the trot.
Martin Scott struck post and crossbar with headers for Hibs.
Craig Dargo and Paul McGowan tried to create a spark for the Buddies, but it was Dickoh’s back-post header three minutes from time that won the match.
The goal came late but it was just reward for the visitors who at least looked like they wanted to win the game.
St Mirren were booed off the park by disgruntled fans after a display that completely lacked in attacking adventure.
Saints had started the brighter of the teams. An error by Callum Booth allowed McGowan a brief sight of goal but Hibs managed to snuff out the danger.
The visitors’ first chance fell to midfielder Scott, who hit the outside of the upright in the 13th minute with a near-post header.
McGowan looked lively for the hosts but they could not find a breakthrough before the interval.
Derek Riordan volleyed a difficult chance just over from 20 yards but St Mirren came back into it and Graham Stack did well to hold McGowan’s left-footed strike from the edge of the box after St Mirren had worked the ball inside following a throw-in.
The half continued in a scrappy fashion amid windy conditions with Hanlon defending well for Hibs as St Mirren tried to exert pressure.
Scott hit the woodwork again in first-half injury-time after Akpo Sodje’s flick-on but Paul Gallacher had his looping header covered as it struck the top of the bar.
The Saints keeper looked less certain, though, when Riordan received a clever pass from Scott and flashed a shot from 18 yards which Gallacher fumbled out for a corner.
After an hour of play, Dargo ought to have tested Stack but his attempted chip from the edge of the box sailed a few feet over the bar.
Dargo’s deft back-heel 30 yards from goal allowed Michael Higdon to progress towards the box but the big striker’s lay-off was disappointingly heavy and the sniff of goal evaporated.
Victor Palsson and Lewis Stevenson were booked by referee Euan Norris for crude challenges on St Mirren’s Paul McGowan and Steven Thomson respectively as the scrappy nature of the match continued in the second half.
Hibs had enjoyed the bulk of possession and, though neither side could be described as threatening in front of goal, had looked the team more likely to break the deadlock.
With three minutes remaining, a draw looked a certainty until Booth delivered a high, looping corner which was headed back across goal by Hibs captain-for-the-day Hanlon towards centre-half Dickoh who rose to head home.
Hibs: Stack, Dickoh, Hanlon, Booth, Towell, Wotherspoon, Miller, Martin Scott, Palsson, Riordan, Sodje.