Conor Newton’s strike for the home side was cancelled out by Dale Carrick as Gary Locke’s side finished a difficult campaign with just one defeat in their last eight games.
Over 2,000 fans were packed into the away end, and it would be fair to say a number of them were following events at Easter Road with equal interest.
Jamie Walker’s early effort warmed Christopher Dilo’s gloves and Walker was soon threatening again after good link-up play with Sam Nicholson.
Dilo spilled a cross but Carrick was unable to profit before the danger was cleared and Hearts were made to pay moments later.
Newton (28) followed up after Jamie MacDonald had made a good stop to deny Kenny McLean, slotting in from a narrow angle.
Josh Magennis headed narrowly wide from the impressive Gregg Wylde’s cross as St Mirren pressed for a second while McLean drew another good save from MacDonald with a 25-yard free-kick.
Carrick (48) then pounced as Hearts hit back on the counter, the midfielder gobbling up the extras after Dilo spilled Walker’s shot.
McLean was again trying his luck but MacDonald was alert to the danger and Magennis and Paul McGowan both went close but Callum Paterson came nearest to a winner, only to be denied by Dilo.