The Buddies needed the help of the woodwork late on to save the point.
The Slovakian keeper denied David van Zanten, Paul McGowan and Graham Carey in the first half although Jambos midfielder Eggert Jonsson missed the best chance of the game just after the break when he headed into Craig Samson's arms from close range.
Kello made his best save of the day when he tipped a close-range drive from substitute Nigel Hasselbaink over the bar before a late strike by Jambos substitute David Obua beat Samson but hit the inside of the post before rebounding clear.
In the end it was a point apiece after what was one of the better goalless draws likely to be witnesses this season.
St Mirren boss Danny Lennon made one change to his side with Gary Teale replacing the injured Jon McShane.
With Ian Black and Danny Grainger both suspended, Paulo Sergio was forced into two changes with Ryan McGowan and Mehdi Taouil coming in.
The Hearts players discovered yesterday that their overdue wages had been paid, which presumably gave them a boost going along the M8 to Paisley. The news came 24 hours after the squad were persuaded not to make a formal complaint to the Scottish Premier League by Sergio.
However, the first half was mostly about visiting keeper Kello keeping St Mirren at bay.
The home side had the edge in the early stages and in 15th minute Teale set up van Zanten after cutting inside Gorgie stopper Andy Webster but the right-back's drive from just outside the box was tipped past the post by Kello for a corner, which the visitors defended.
The Slovakian came to the rescue of the Tynecastle side again in the 24th minute following a swift Saints break.
Midfielder Paul McGowan picked up a raking pass from Carey, played a one-two with left-back Jeroen Tesselaar but his low drive from 12 yards was saved by the Hearts keeper at the near post.
Just after the half-hour mark, as Hearts countered, Carey tripped David Templeton at the edge of the St Mirren box to prevent him getting on the end of a Ryan McGowan pass but Rudi Skacel's shot from the free-kick came off the Buddies' defensive wall and flew away from the danger zone.
Kello was called into action once more in the 36th minute as he threw himself to his right to palm Carey's powerful long-distance drive past for another corner, which he plucked out of the air to the cheers of the travelling fans behind his goal.
Meanwhile, efforts from Jonsson, Taouil, Ryan Stevenson and Skacel had all flown wide of the target.
David Barron replaced van Zanten for the start of the second-half and within two minutes of restart St Mirren midfielder Kenny McLean had fired just over the bar from 20 yards after being set up by Teale.
However, in Hearts first attack of the second half Jonsson got to Taouil's cross from the left first but from six yards out he headed straight into the arms of Samson, thus squandering the best chance of the game.
In the 50th minute Kello reacted late to tip a wayward Carey cross over the bar but again St Mirren failed to take advantage of the set-piece. Five minutes later Obua replaced Taouil as Sergio looked for a different approach but in the 57th minute it was the Paisley side who again came close to getting the breakthrough.
Carey's powerful shot from the left was going wide but Saints striker Steven Thompson bravely dived to get his head on the ball which came off the top of the bar before going over.
As the game warmed up, Samson made a decent save from Templeton's drive and from the resultant corner, Obua's header sparked a goalmouth scramble which the home side somehow survived.
Lennon then made a double substitution, Hasselbaink replacing Teale and Illias Haddad on for Paul McGowan.
Stephen Elliott came on for Adrian Mrowiec just before Kello made a great point-blank save from Hasselbaink who blasted in a shot from just six yards out.
In the 82nd minute there were claims for a penalty when Hasselbaink's cross from the by-line was blocked by Obua but referee Steve Conroy gave the corner.
Andrew Driver came on for Templeton with four minutes remaining before McLean's half-volley from the edge of the box was blocked by the head of Marius Zaliukas for another fruitless Saints corner.
In the 88th minute Obua's dipping drive from 30 yards beat Samson but struck the inside of the post before somehow staying out but a late winner for Hearts would have been an injustice.