Brixley began her career in the Brotherhood as a scout/explorer. She was originally sent east to confirm the existence of Maxson Bunker and to use it as a staging area for her explorations. She was accompanied by a team of four paladins.
After the war broke out between the BOS and the NCR, Andrea was promoted to commander and placed in charge of the bunker. She also received the title of Elder Paladin, as did her four companions. Andrea is not comfortable with leadership and would prefer to spend her time exploring. She isn't very organized and is content to let people do what they are best at with little supervision. Fortunately, her supporting staff recognizes her flaws and cover for her.