Her past isn't something she talks about much; it's not important, as far as she's concerned. She was a US Marshall for a time (one of the youngest to rise through the ranks), but lost her credibility when she became obsessed with finding the fugitive known as The Desert Wolf. As a result, Braeden turned to mercenary work to make a living. In the course of that work, she learned about the supernatural, and the means of defending herself against it. 

There were times she might have felt guilty for what she did on the job, but she rationalized that if she didn't, someone else would. . . The first time she started caring about who her job hurt was when she was hired to find Isaac Lahey, and met with the local pack of Beacon Hills. Fate kept throwing her into their orbit, over and over again, and soon she fell in love with her client--something she swore to never do. For the first time in years, Braeden had someone in her life who gave her a reason to want to put down roots.