Qualifications
None. Zip. Not a one.
As long as you have the cash to buy in, any well-operated gambling establishment will let you play on their tables—and why wouldn't they? Your money is just as good as any other player's; as long as you're not some wildcard throwing cards everywhere, they'll take it as long as you're willing to spend it.
There are no qualifications for making a seven-figure income either. You could walk right off the street, sit down at a random table, go all in every hand, and walk out a millionaire. That's half the reason people play this game in the first place (the other half being it's the only place you're allowed to wear sunglasses inside).
However, if you really want poker to be your career, there are ways to enhance your potential for success. Most top pros have read dozens of books on poker strategy, watched and studied countless hours of video, verbally gone over hand histories with their poker friends, and spent far too many hours analyzing mistakes made in past play.
This is what separates the true professional from the lucky newb. If you're looking to get into poker as a way of avoiding any amount of studying, training, or preparation, you may find that you're losing an awful lot of games.