I don't know of any long term profitable sports gamblers - but that makes sense because why reveal yourself and your methods if you're profitable?
By long term I mean at least 1,000 bets while still being profitable. Even more impressive if they are making a living off of it.
The only person I can think of is Picks Office on Twitter.
All they need to do is check if you're cashing out more chips than you came in with.
A buddy from out of town, or a losing regular, or a poker player who the casino doesn't care if they win. In Vegas some casinos' chips are negotiable, officially or unofficially, in other casinos.
They rightfully passed legislation banning such practices. The idea is that if casinos and bookies refuse to cap your downside, they have zero right to cap your upside.
The bigger the market the harder that is, so maybe it doesn't apply at the level of online sports betting. But organized crime could make trouble at horse tracks.
It helps if you can also rig the race, but just knowing the odds better than the pari-mutuel stakes gives you an advantage.
https://www.theguardian.com/football/2025/dec/05/brighton-ow...
I have a very small edge in sports betting although I don't really do any of the deep overpriced/underpriced arbitrage or any special types of bets outside of wins/loses. And it's limited to tennis, a sport I've played my entire life and have followed the pro circuit closely for 3 decades. And even then my edge is very small, and the strategy I use when I do bet doesn't make me much in total return.