actually tony was the underboss from season 2-6
junior was the boss......tony was the underboss
tony became boss in season 6 and paulie became underboss
bobby was being groomed to be underboss but he wasn't there yet
Tony was "Street Boss" and later acting Boss (now I'm not a mafioso so I don't know what the actual difference is between "Street Boss" and "Underboss", if there is one. I would guess that traditionally an Underboss didn't get his hands dirty, while Street Boss did). He was never the official boss of the family, although he had all the power.
Actually if I'm not mistaken, Junior (and Jackie Aprile before him) were just "acting boss" since DiMeo was alive (albeit in prison for life) and I don't think it was ever said that he died, so technically he never gave up the the title of Boss, although he couldn't do anything with it except perhaps use it for prison cred.
