[wemple2]

I tend to agree with the others. Keep him on leash. Put yourself between him and other dogs. Start out on a slow day at the park, then increase instances. Praise him for good behavior, stop him in his tracks for bad behavior. Remove him from the area/park. Each time you return to the park, on leash, if he acts out...stop him and remove him. But keep trying, eventually he will understand what you want from him, these are smart little critters and they aim to please. Show your pleasure when he's behaving properly, this will encourage good pet behavior. Good luck and keep us informed.