Yep. I’m an officially minted PhD historian and adjunct professor.
In terms of how to pursue a career in history, in general terms, you probably need a BA in history (although I imagine you could get away with a BA in interdisciplinary studies), then you apply for grad school in history, then you get a degree and you try desperately to get a job. If you have more specific questions, I’d be happy to answer them.
I feel it’s important to say right at the start that the history job market is really bad right now; there’s way too many PhDs for the number of jobs out there, there’s fewer and fewer full-time positions and a lot of us are working part-time. So you need to be sure from the start that this is something you really want to do, and you absolutely need to make sure that the program you’re applying to will provide full funding, because you don’t want to go into debt getting a history degree.
However, there are options for jobs outside the academy if you go through a history program which can give you a credential you can apply towards working in a museum, or something like that. In my case, I got my degree in the history of public policy, and now I teach in a public policy program rather than a history department.