The real answer is there probably isn't a sufficient condition for success, but hard work in pursuit of your own goals (rather a manager's) increases the likelihood of a positive outcome.
Still, I'd have gone a step further. 'Career' is such a false construction. Go do fun shit and get really good at it. Maybe I'm naively optimistic, but if you're really good at something, it's pretty easy to get paid (a lot) for it.