Sounds like the terrier in him.
The wonderful thing I've found with my terrier is, he knows when to let all that excess energy go. In the house he's a couch potatoe, but once we get in the woods? He's a nut bar, running for hours straight sometimes.
As others have said, it sounds like he's not getting enough excercise, OR not enough of the RIGHT KIND of excercise.
Walking on leash for some dogs just doesn't cut it. THey need intense running, for sometimes long periods of time.
So playing fetch (I'm talking throwing balls 50 feet 50 times in a row! haha), swimming, long off leash hikes etc etc are sometimes what certain breeds/personalities of dogs require regularly.
007's idea of giving the dog a job is a great one IMO. Dog's with jobs are often happy dogs.
