Can I count myself self-employed if I devote significant time/research to gambling and it's my primary income? Min income req? What fed/state tax should I expect (MI)?

If gambling is your full-time occupation and your primary source of income, you can probably file your tax return as a professional gambler. There is no specific minimum income requirement. However, the IRS or your state might challenge your use of that status. They take a hard look at people who claim to be professional gamblers. I suggest that you consult a local tax professional before you do it.

A professional gambler does file as self-employed. However, even filing as self-employed, you still cannot deduct losses in excess of your winnings. In other words, you cannot claim a net loss.

You would pay regular income tax plus self-employment tax on your net profit. The amount of tax depends on a number of factors, including your filing status, the amount of income, the amount of any other income you have, and any deductions or credits you might be entitled to. The tax professional that you consult may be able to give you a rough idea of how much tax you would have to pay.

@boo_ster 

You might want to review this webpage from the IRS:

https://www.irs.gov/newsroom/earning-side-income-is-it-a-hobby-or-a-business