A regular harness probably won't work, they don't on most dogs. I'd try a 'no-pull' harness if you want to try a harness at all. Has he been to obedience classes? If not, maybe he and you should enroll in some and maybe they could help you learn a few things when it comes to pulling? I personally prefer the prong collar for dogs that are almost impossible to walk, I use it one Tang at the moment eventhough she does have a perfect heel. if she sees another dog or a bird though, she pulls horribly and the prong collar is the only way I can stop her quickly as when she's focused on something, I don't exist. We're working on that though and I rarely use the collar any more. Most of the time I walk her on a martingale now. The prong collars are not cruel as people seem to think, I've tried it on myself once before I bought it just to see how it would feel and it didn't hurt at all. It was a tiny bit uncomfortable, but it did not hurt. Just make sure you know how to use one properly. There are is also the Halti, Gentle Leader and other types of head collars that people say work but when I used it on Tango she was miserable. Other people disagree with the use of any sort of training collar which is what the prong collar is but it's worked for me in the past, aswell as many other people. Maybe somebody else has some better advice though..