Aldous asks:First time I've heard that. Are you sure? That would have meant a whole new career path.
Hmm...well now I'm not so sure. I was thinking of the account in Gary Grossman's "Superman: Serial to Cereal," but it's been a number of years since I dug that out so I could be remembering incorrectly.
A quick Google search shows accounts that could go either way. One site says George fought as an amateur before his mom put a stop to it (worried he'd ruin his looks), other sites merely cite a boxing "career" and one says he won 31 bouts with no losses by age 20. But it's unclear what his status was as far as "professional" or not.
In my estimation, if you get paid to do something, you're a professional. But I can't find anything that states unequivocably that he made a living, or even an appreciable side income, doing this.
Then again, I happily know very little about boxing, so maybe there's a more specific, regulated definition of what constitutes "professional"?
Anyway, as far as a "whole new career path," George was 45 at the time of his death and that's over the hill for just about any sport.