Pearson has now won two and drawn one of his three games in charge since the departure of Bryan Robson.
The success against managerless Leeds was all the more impressive as Albion had to play the final hour with 10 men after the dismissal of Paul McShane. But the margin of their victory was a lot closer than it should have been.
Albion had powered into a 3-0 lead before Leeds almost pulled off a Great Escape with late, late show.
Goals from the former Albion striker Geoff Horsfield and Steve Stone fired Leeds in sight of an improbable point before Diomansy Kamara ended their challenge with his second in stoppage time.
While the win has boosted Pearson's job prospects, it did nothing for those of Leeds' caretaker boss John Carver.
He was forced to sit and watch his side soak up long periods of pressure before they came to life in the closing stages.
It could all have been so different had David Healy not missed a 32nd minute penalty after McShane was sent off for hauling down Horsfield.
In terms of chances created Albion were well worth the half-time advantage Martin Albrechtsen had given them. But the surprise was that it came after the dismissal of McShane and the subsequent miss from the spot by Healy.
McShane saw red after hauling down Horsfield. Referee Rob Styles had no hesitation in pointing to the spot or dismissing McShane.
It presented Healy with a golden chance to break the deadlock but he dragged his spot-kick wide - and was punished by Albrechtsen.
Despite Leeds' one-man advantage, Albrechtsen was left unmarked at the far post to head home Jason Koumas' corner.
Kamara, making his first Championship outing of the season after a broken foot, stabbed home Darren Carter's cross at the far post in the 65th minute to double their advantage.
Kamara then turned provider 11 minutes from time - setting up Kevin Phillips to steer home from close range.
That should have been game over only for Leeds to come alive. Horsfield drilled home a low drive from Jonathan Douglas' pass in the 82nd minute and Stone then fired into an empty net after Horsfield had hit the post before Kamara ended their late cameo by chipping over Warner in stoppage time.