It had looked as though the Saddlers were on their way to an easy victory when they went two goals ahead after only 13 minutes and dominated for most of the first half.
But Danny Wilson's men turned it round in a frenetic second half and with Walsall failing badly the northern side ran out deserved winners.
Walsall went in front after only four minutes when Michael Ricketts headed his fifth goal of the season at close range from a penetrating corner by Chris Palmer.
Nine minutes later Jabo Ibehre also took his season's tally to five goals with a header, this time Troy Deeney providing an excellent cross.
Hartlepool didn't get into it until the 22nd minute and even then big striker Kevin Kyle headed goalwards from a free-kick by Richie Humphreys only for Clayton Ince to save comfortably.
In the 34th minute Kyle missed badly with a free header from a cross by the clever Ben Clark.
Seven minutes after the interval Deeney missed a great chance to sew it up for the Saddlers, but drove wide inside the six-yard box from a cross by Palmer.
Hartlepool manager Danny Wilson made some decisive substitutions in the 64th minute bringing on Matty Robson for Joel Porter and David Foley for Andy Monkhouse.
It took only eight minutes for Robson to make his mark, cutting through down the left and crossing for Antony Sweeney to reduce the arrears with a low shot.
Four minutes later Robson equalised with a cracking drive from 25 yards, following excellent build-up work involving Clark and Kyle.
Walsall, who had been on the back foot for virtually all the second half, were further punished in the 84th minute when the impressive Sweeney crossed and James Brown notched Hartlepool's winner with a superb header.