i would take him to classes, cause there public, i would go to basic obedience however you spell it, even though he may know all the commands in the class it teaches him to do it, in public places, nobody is rewarding him when he jumps up right (meaning nobody is petting him when he does jump up)?

Go to petsmart with him, let nobody pet him, and have treats with you, everytime he looks up at you give him a treat, say good watch me, adventally he will know that when he looks up at you he is good. also once he starts looking at you ask him to sit if he does tons of rewards. if he doesn't say it more stern. If he dosn't after that then push his butt down lightly when he does sit say good boy, be happy give him treat and then he will catch on too.

For at the situation at home, if he is happy to see people that's good, but when he jumps up on people say off, take him away. don't let people pet him when he jumps on them because thats like him getting praise for jumpig up.
good luck with that