Thanks for the additional information. I really appreciate it.
First and foremost...it is completely understandable that your dog is acting up at this point... the alpha roll is very much the wrong thing to do on many, many levels. The 'alpha roll' is NOT something that should ever be done to a dog by a person. First, if you're dealing with a fearful or reactive dog (which you may be at this point), then that's going to make things worse because this is essentially a bullying tactic. Humans never, never, never get the timing of the roll correctly because a dog reacts in less than 5 seconds. Next, it's a good way for a person to get bitten...so I implore to you to please stop using this tactic with your dog.
To me, it absolutely sounds like you have the perfect example of a head-strong arctic breed on your hands. This breed of dog, possibly more than any other breed, is infamous for their energy, hyperactivity and habit of getting themselves into trouble. Although it will be a great deal of work, this behavior CAN be changed.
The first thing you're going to need to do is get him on a strict regimen of exercise. I understand that you may have a busy life and things to do, and may be worried about taking him out, but these working dogs NEED to be exercised every single day, and I'm talking more than a quick walk around the block. A high energy dog like this needs a couple miles a day to drain his energy and keep him from getting into trouble because he's too wound up. If you are unable to walk him, you may want to consider hiring a pet walker. In my neighborhood, I live close enough to the colleges that I put up fliers at the schools and hired some of the track runners to take my dogs for a run on the days I can't. I pay them $10-$15 bucks a day, and it really, REALLY works. The dogs get the exercise they crave, and the students get a couple bucks in their pockets for doing something they would have done anyway (the running). Several of my runners say that they feel safer running some of the woodsy trails around here because the dogs 'look' scary enough to ward off anybody who might bother them (luckily the strangers don't know that my dogs are all big marshmallows!!).
Additionally, he should be walked with a Gentle Leader. I guarantee that he will eventually get used to it, and it will make him easier to control in the walking. The general rule of thumb is that if you control the head, you control the dog, so putting the leader on and leaving it on during the walk, regardless of how much of a temper tantrum he throws is key. When he starts pawing at the Leader, simply give the leash a tug, say "Leave it!" and continue walking, even if it means you have to pull him along for a minute or so. Physics tells us that the dog can't paw at his face and walk at the same time...if you keep him moving forward, he'll have no choice but to leave the Gentle Leader alone.
Secondly, you might want to consider clicker training this dog. This involves buying a 'clicker' which has a little metal plate in it. You press the plate and the thing clicks, then you give the dog a treat immediately. Soon, the dog learns that the click brings a treat and will usually drop whatever they're doing, which includes trying to get into altercations with other dogs on the walk, and even will help him focus on you during the walk. http://www.clickertrainusa.com/clicker-training-videos.htm .
If you feel like he may be too anxious to wear the Gentle Leader or do the clicker training, you may also want to look into trying an over-the-counter product to help him with his anxiety.
A couple things you could try would be:
Melantonin is an over-the-counter drug that can be used to treat some anxiety issues in dogs. The dose you would give would be up to 3 mg given orally whenever necessary up to every 8 hours. More information can be found here:
http://www.petplace.com/drug-library/melatonin-melatonex/page1.aspx , which includes risks, warning signs to watch out for and other bits of useful information.
Try a DAP collar. These are collars that are impregnated with a man-made version of the dog appeasing pheromone, which is a pheromone that nursing bitches give off to their pups to help them feel calm and secure. It's something that humans can't smell, but it has an amazing effect on dogs with anxiety and other issues. Although you can find them at your vet's office..you can also find them online at places like Amazon.com and Ebay for much cheaper. Just make sure they're DAP brand, as they seem to work better than some other versions.
I definitely think that with a combination of the Gentle Leader and longer walks you can get him in line and get him to stop being so leash reactive.
I hope this helps.