Leigh Griffiths lit up a match otherwise dripping with mediocrity, deservedly notching the only goal.
The Hibs striker nonchalantly tucked a penalty past Craig Samson after Jim Goodwin was penalised for a push on Matt Done.
He might have been on the scoresheet previously, but the post denied him a wonderful solo goal.
St Mirren managed to force Ben Williams into action just once, to block an Esmael Goncalves shot.
Goncalves was St Mirren's most potent threat, but had little help from his team-mates who looked off the pace throughout.
Hibs weren't great either, but, in Griffiths and Paul Cairney, possessed sufficient quality to claim victory.
A really turgid opening quarter to the match was almost banished from the memory by a phenomenal piece of skill from Griffiths.
Bringing the ball under control with a perfect first touch on the right wing, he glided past two challenges, nutmegging Goodwin, before unleashing a ferocious drive from the edge of the box.
But, though it had the beating of Samson, the striker watched agonisingly as the ball rebounded back into play off the post.
St Mirren's first real chance fell to Paul Dummett, but his back-post header drifted across the face of goal.
Goncalves did his best to lift his side and almost forced a goal just before half-time with a powerful run and shot, but Williams, with virtually his first touch, was able to push the ball away.
Hibs' greater attacking threat continued at the start of the second period, with Done's cross begging to be turned into the net, but as Cairney stretched to do so, his team-mate Tom Taiwo got there marginally quicker and glanced the ball wide.
Griffiths had a free kick comfortably saved but was soon presented with an easier chance to score as Done went to ground in the box, with Goodwin in close attendance.
Referee Willie Collum decreed there had been a shove and Griffiths rolled the ball coolly into the net as Samson dived to his left.
With 11 minutes remaining, the St Mirren keeper did well to keep out a swerving drive from Griffiths, but even when he departed the field shortly afterwards, the home team couldn't fashion a decent goalscoring chance and Hibs held on with ease.