Before becoming a true 70's juggernaut with licensed lines like "Star Wars" and the "Six Million Dollar Man", Kenner was more experimental with their action figure branding, often creating fun generic lines such as Steve Scout and Duke The Dog.
Duke truly was an original concept, never had a toy line such as this been tailor made for a character who didn't even wear pants. The resulting toys were kind of surreal but oddly cool.
Duke lasted a couple of years actually and would see TV star "Run Joe Run" added to the line as well.
More Goodness from the fine people at Kenner:
Over at Sitcom Diablo I've penned a list (I know) entitled "The worst Sitcom replacement characters ever" Please do check it out.