The former West Ham striker nodded home just three minutes after being introduced to ensure Pools kept their noses ahead of Cheltenham in the scrap to avoid the drop.
There was a palpable sense of tension in the opening exchanges as Ronnie Moore’s men, entering the clash on the back of successive defeats, struggled for a foothold.
And it was no surprise when Accrington were rewarded for a confident first-half showing in the 38th minute, Josh Windass powering home a half-volley in fine fashion from Sean Maguire’s knock-down.
Pools looked the better team after the interval, but almost fell further behind when Scott Flinders produced a wonder save to keep out Piero Mingoia’s deflected effort.
That stop looked even more important soon after as Harewood rose high in the area and superbly headed Jordan Jones’ pin-point cross into the corner.
Hartlepool pressed on in search of a winner and almost grabbed it in injury time, only for Scott Fenwick to slide over from Neil Austin’s centre with the goal gaping.