Every dog has his own personality and some are more rambunctious and excitable than others. More often than not, a dog acts in a boisterous manner because he's not being stimulated sufficiently and has too much energy. Several methods exist for getting your rambunctious dog to calm down.
If you're looking to get a dog under control, the first step is to train him. A dog who has never been taught to obey commands isn't going to magically have perfect behavior. If you're no expert in dog training, it's a good idea to look out for an obedience class that runs in your area. Only attend classes that teach positive reinforcement training, as it's the most humane and effective method. Ask your vet if you need a recommendation.
The Silent Treatment
Giving your dog attention when he's acting in a rambunctious manner can reinforce the behavior and cause him to act this way more often. Even negative attention, such as yelling or scolding, can still reinforce boisterous behavior -- think about toddlers who throw tantrums for attention. When your dog is acting out, completely ignore him -- don't touch him, talk to him or even look at him. Once he's calm, praise him or give him a treat. He'll soon learn that he gets more out of acting calm.
Your dog may be acting rambunctiously simply because he's full of beans. If he's not getting enough exercise, he'll have a bundle of excess energy that he doesn't know what to do with. Ensure that your dog is being walked enough for his size or breed. You could consult your vet if you're not certain about his exercise requirements. Ideally, larger dogs should have some off-leash time to run freely, but only if you walk him in a secure area where he's allowed off the leash. Otherwise, a long game of fetch in a secure yard will allow him to stretch his legs, in addition to his daily walks.
Jobs for Dogs
Rambunctious dogs sometimes just lack focus and benefit from feeling like they've got a job to perform or a purpose. You can participate in various activities with your dog, which will stimulate him both mentally and physically and may help to calm him down. Possible activities include agility, the American Kennel Club's Canine Good Citizen Program, flyball, working trials, heelwork to music and dock diving.