You could be kept on the bench. The other team’s pitcher hits one of your guys, you get put in for retribution, putting their batter into the hospital. A few demonstrations of your abilities and either teams respect the heck out of you, or maybe MLB changes some rules.
Definitely pro wrasslin’. The big thing would be learning not to accidentally hurt anyone. I’d need to save my money, since the novelty would run out at some point with the territory system dead and gone.
Being a pro wrestler has very little to do with strength. Stamina and agility are more important. Plus, unless you LOOK like a bodybuilder, you won’t draw an audience.
Maybe be a pro golfer? You’ll have the strength to drive the ball literally wherever you want and even the smallest guys can generate power, so a small frame wouldn’t look too terribly out of place.
You’d have to work on form for chip shots and stuff, but that can be done. Or maybe just a pro long-baller.
But that assumes you won’t ever have “good form and training”. Just because you’re super-strong doesn’t mean you can’t also learn form. And you’d have an advantage over every other athlete, because you wouldn’t have to spend hours a day in pure strength training - you could devote all that time and effort to skill development.
I suppose it would depend heavily on when in your life you learn this about yourself. Trying to break into the NFL would require you to start early, getting on your high school team, and eventually a college team, to be drafted. It’s very unlikely that any team would even look at a middle-aged guy who just shows up looking for a try-out, even if he could lift a few thousand pounds.
Other, more individual sports might be easier to break into. What are the requirements for becoming a professional golfer?
You will if you can casually press Andre-The-Giant-sized guys over your head.
Also, I said that the gimmick would run its course fairly quickly. Hence the importance of saving money. I think it would be a matter of taking a year’s leave of absence from my job (after training). A couple of times around the horn as a special attraction, and back to my day job.
Actually I have boxed and at least personally I can’t/couldn’t learn good form or technique. 
You can’t do any true combat sports because if you’re superhumanly strong even a pulled punch will probably kill a guy.
nm
The only strength related thing that I can think of that would make as much money as my current salary would be as a professional athlete, and with my balding droopy over weight physique, it would certainly raise eyebrows that I can throw around 300 lb behemoths as a football player. The best I can probably do is keep my day job, and then spend the evenings roaming bars and winning bar bets to pick up some extra cash.
I admit that my first thought also was “lifting safes for fun and profit”, but you have convinced me that crime is not the way to go. But what if I took that literally? Professional safe and other heavy object mover and installer?
I’m reminded of a bit in one of the Wild Cards novels (alien meddlers inflict superpowers on humans because they’re too chicken to do it to themselves) in which someone’s looking for an actual alien who’s got super-strength; he goes to the dock where the guy works and he’s told to “look for the guy who’s not using a forklift.”
I would move my own furniture and save a fortune on chiropractic bills.
Well, if you go the crime route, I think one thing folks are missing is…armor. One reason why humans don’t wear that much armor is that the stuff is heavy. If you have an issue with your skin, but you have the strength, including the tensile strength in your bones to support hundreds or thousands of pounds, you could build some fairly impressive and, for all intents and purposes impervious armor. Sure, someone with an RPG or the like could probably take you down, but who is going to bring that to stop a bank robbery? They would assume whatever armor you had would have the same constraints as any armor a human could wear, at least initially. Plus, it would presumably protect your identity. I’d advise no cape though (see Incredibles for details)…
If it were me though, and this happened right now, at my current stage in life? Well, there wouldn’t be that much I could do. Personally, I’d probably contact some people I know who work in the labs, bank on my reputation and friendship to set up some demonstrations, and then set myself up as a private consultant for testing. I could make bank with that, if I could get the right people involved, and I have several ideas there. First though I’m thinking I’d take one of those million dollar challenges to demonstrate paranormal powers. Again, I think you could swing that, especially since you get to work with them to set the conditions. Say something like ‘I will demonstrate my paranormal psychic powers to allow my body to lift this car with one hand. You can test the car by weighing it, and put on any sensors or whatever measuring equipment you like, you can film it, but I want a 3rd party there as well so you don’t try and weasel out when I do it. You will get all rights to the video of it to put out on any channel you like, as long as your check clears. Deal?’. I think I could make an easy million there, then with my consultant gig at the labs I would be set. It would, perhaps, suck to be a test subject, but for enough money I’d do it, especially with the right contract. I don’t think I need to worry much about a shadowy government kidnapping me for secret experiments if I’m already known and on the books to do this stuff in the open. The US government would pay a lot for this…and THEY would protect me from those nasty Russia or Chinese spies trying to snag me. 
Do you live somewhere net electric metering is popular? Spread the word that you have a device THEY don’t want the public to know about! A way to adjust home meters so they think they’re feeding hundreds of kilowatts back to the power company! For just fifty dollars once a month you’ll come to people’s houses and reduce their electric bill to NOTHING! Advertise anywhere you’ve seen adds for cable descramblers. Use lots of technical terms. The device is actually a generator, powered by your awesome superstrength, and that’s why you have to keep coming back every month.
Scuplture kidnapping! Find some valuable object that’s left out in public because no one could take it away without a forklift. In the dead of night, wearing a mask, move it a few feet. Leave a note tucked underneath promising not to do it again if a bag of small unmarked bills is left in a suitable difficult-to-monitor location.
I would literally shoplift.
This is what I was going to say at all the mentions of boxing. If a full strength punch goes through steel, I’m thinking in a boxing ring that there would be a very fine line between a KO punch, and an inst-kill punch.
Worlds Strongest Man comps seemed an obvious avenue, but upon research doesn’t appear to actually pay all that well. The biggest winners cheque is apparently ~$70k for the Arnold Strongman event. So presum8ng the other events are quite a bit less, I suppose you could still earn a couple of hundred k a year for what realistically would be a few days work. So not stupid rich but pretty comfortable, with plenty of spare time. But even here there’d no doubt be questions about how a middle aged overweight guy was easily beating absolute hulks like Eddie Hall or Bjornson.
If the police figure out that shooting you is ineffective, eventually they’ll resort to pepper spray and tasers to establish control over you and enable them to remove your armor. The only way brute strength will allow you to live a life of crime (in the long run) is if you use it to commit crimes and escape quickly before anyone can intervene or ascertain your identity.
"We can’t accept this diamond – it’s got fingerprints stamped into it.
Besides, it’s completely without provenance."
In the movie The Gladiator (based on the Philip Wylie novel “Gladiator”, which is pretty generally believed to have been one of the biggest influences on the creation of Superman), the hero, super-powered Hugo Kipp (Hugo Danner in the book), takes to exhibition and competition wrestling to make money. In the novel, he makes money as a professional wrestler and as a strongman.
You could make money those ways, but, I suspect, not BIG money. Maybe you could if you managed your career right.
(Ironically, although the novel was straight science fiction drama, the movie was a comedy, starring Joe E. Brown, and came out two months after the comic Superman hit the newsstands.)
What about being a professional cyclist? Like competing in the Tour De France? I admit I’m more than 100% ignorant to sport biking, but my dumb logic says that if superhuman strength translates to leg strength as well, you could just power pedal the whole thing, no? You wouldn’t even need that much stamina because one or two leg pumps would keep you going forever, even up mountains