Can my boss fire me because I wear an ankle monitor?
Unless you have a written employment contract protecting your employment, you are an employee at will, which means you may be terminated for any reason--including wearing an ankle monitor.
Wearing an ankle monitor is often a better alternative to either jail or home confinement for all the obvious reasons: it gives you the freedom to be where you want and go where you want. But if there is any way to have your freedom without the monitor, even if it puts other restrictions on you (e.g., having to check in periodically with some officer), you may wish to consider it, because you can be legally fired or terminated for wearing an ankle monitor.
It's not that the law specifically states that an ankle monitor is grounds for termination. Rather, it is that “everything” and “anything” are grounds for termination in this country, unless you have a contract prohibiting your employer from terminating you for that reason, or the reason is one specifically made illegal. That's because employment in this nation is "employment at will": you have a job only so long as it is your employer's "will," or choice, that you have one. You can, as a general rule, be terminated for any reason at all, including something as silly and irrelevant as disliking "Game of Thrones" when your boss is a GOT fan.
The protection afforded by a contract is fairly straightforward. If you have a written employment contract for a definite term (e.g., a one-year contract) which is still in effect and which states you can only be fired during that period of time for certain defined reasons, then unless "ankle monitor" or “criminal conduct” is one of those reasons, you cannot be terminated for it. If an employer violates a written employment contract, the employee can sue for "breach of contract" for a court order requiring the employer to obey the contract, and/or for monetary compensation.
If you are not protected by a contract, then the only restrictions on terminating you are that you cannot be fired for certain specifically defined discriminatory reasons, the main ones of which are that you cannot be fired due to race, color, national origin, religion, sex, disability, or age over 40. However, having a criminal record, or being charged with a crime, or wearing an ankle monitor are not protected reasons on a national level (that is, federal law does not prohibit terminating someone for one of these reasons) or in any state at this time (September 2017). While it's worth double checking the law of your particular state, to see if perhaps your state does bar employment discrimination due to a criminal record or criminal charges (which would very likely also bar termination due to wearing an ankle monitor), it is very unlikely that it does. U.S. employment law gives the employer very wide latitude to terminate people due to anything connected with criminal activity, which would include the wearing of an ankle monitor.