Paul Mullin gave the visitors a deserved lead in the 16th minute, but Colin Murdock's unlucky own-goal gave the home side hope.
And that hope was rammed home in the second half as the hosts had the better of the chances and it was Harold who netted the winner with just ten minutes remaining.
It was Harold's 12th goal of what is proving to be a successful season - and also his fifth goal in the last eight games.
And how the home side needed the former Yeovil Town and Southend United striker's input as Stanley went close to snatching a draw.
Accrington started brightly and Mullin headed wide from a good position after just seven minutes.
Three minutes later Phil Edwards also went close for the visitors, but his powerful shot flew wide of the target.
Chris Zebroski then headed wide at the other end with Wycombe's first decent chance of the half.
Then Mullin gave the visitors a deserved lead with his second goal in three games. Having controlled the ball well on his chest the experienced forward didn't waste his chance to hit the back of the net.
But just six minutes later the hosts were on level terms. Gary Holt's pinpoint cross found Zebroski and his cross-cum shot was deflected in by Murdock.
Chris Casement then fired wide for the home team, before Tommy Doherty had a shot saved by Stanley keeper Kenny Arthur.
Angelo Balanta shot over in the 32nd minute - and ten minutes later had a shot charged down on the edge of the area.
James Ryan went close for the visitors two minutes after the restart, before Balanta again had another good chance, but he shot wide from a decent position.
Andy Proctor saw a header saved at the other end as Stanley broke forward, before Doherty had an effort blocked.
Balanta twice shot wide in the space of two minutes shortly after the hour mark as Wycombe pressed for a winner.
And that winner eventually came when Nathan Ashton's cross found Harold and he made no mistake to give his side maximum points.