The already-relegated Tynecastle outfit fought back from Conor Newton's 27th-minute opener to level through Dale Carrick just a minute-and-a-half into the second period.
It was another encouraging display for boss Gary Locke's side as they prepare for life in the Championship next season.
But after failing to get the win they needed to claim seventh-place and their highest top-flight finish since 1989, St Mirren are expected to part company with boss Danny Lennon last week.
The 45-year-old led the Buddies to their first major trophy in 26 years last term when they won the League Cup at Hampden, but the Paisley club's board is frustrated by their team's failure to match the likes of St Johnstone by breaking into the top six.
The game - which saw assistant referee Kylie McMullen become the first woman to ever officiate in Scotland's top-flight - saw Hearts make a bright start as they responded to the backing of an incredible 2,400-strong travelling band of Jambos.
There was a feel-good feeling to their antics just a day after chairwoman-in-waiting Ann Budge signed off on her takeover deal of administration-hit Hearts - and the fact city rivals Hibernian were fighting to avoid relegation alongside them via the play-offs in their last-day showdown with Kilmarnock was making maroon grins even wider.
The visitors came close to scoring but Chris Dilo remained alert in the Saints goal to paw away Jamie Walker's fifth-minute strike. The winger's second effort eight minutes later, though, was easier for the Frenchman to gather.
But it was the home side who struck first just beyond the midway point of the half.
Kenny McLean's probing had become more telling for Saints but when he was given space to shoot on the edge of the box, Jamie MacDonald could only parry to his right and Newton made the tight angle look easy as he slotted in the opener.
A second nearly materialised on 33 minutes when Newton's clever feet sent Gregg Wylde down the left but Josh Magennis put his header wide after his former Aberdeen colleague put over a perfect cross.
But while their team were struggling to get a foothold in midfield, the Hearts fans were suddenly in full voice as news of Kris Boyd's strike for Kilmarnock at Easter Road filtered through.
McLean almost had the home fans cheering too a minute before the break but saw MacDonald push away his dipping free-kick.
But Carrick had the away end in raptures again just 90 seconds into the second period. Walker darted down the right-hand channel but saw Dilo spring to his right to push away his effort. But the bell fell perfectly for 20-year-old striker Carrick to bundle home the equaliser.
Yet Locke's side could not build on their goal as the game grew scrappy.
McLean blasted straight at MacDonald on the hour mark while Jambos substitute Jordan McGhee was booked for mouthing off after giving away a free-kick. The same fate befell Callum Paterson when he let rip at referee Stephen Finnie after being caught offside.
Magennis had replaced Stephen Thompson in the line-up after a tidy-up knee op ended his season early but the on-loan Aberdeen man was having no luck, somehow managing to head seven yards wide from a Paul McGowan cross despite being bang in front of goal.
Paterson should have ensured Hearts went out on a win but Dilo produced a breathtaking one-handed save to claw away his header.
The Hearts fans were still cheering Hibs' latest humiliation following full-time in Leith when the home support rose to their feet to acclaim defender David van Zanten, the out-of-contract Irishman, as he made his final appearance in black and white after 329 games over two spells in Paisley.