Following family tradition, Chief Williams enlisted in the Alliance Marines directly out of high school and was assigned to the Recruit Training Depot in Macapá, Brazil.

During training, she certified proficient with the standard-issue M7 Lancer assault rifle and light and standard weight combat hardsuits. She completed certification in zero-gee combat aboard the Rakesh Sharma Orbital Platform in Earth geosynchronous orbit. For Hostile Environment Assault Training, she was assigned to Fort Charles Upham on Saturn's moon, Titan. She was awarded a commendation for her bold assault technique in a field exercise simulating an attack on turian point defense emplacements.

Chief Williams has served in a number of ground force garrisons on Alliance colony worlds and industrial outposts. She has repeatedly requested transfer to a shipboard posting, but each request has been denied without comment by her superiors.

Every year since enlistment, she has used her mandatory week of leave to visit her family on Amaterasu. In 2181, she made an exceptional request for a week-long leave of absence from her posting at the Czarnobóg Fleet Depot, citing family issues.

Ashley first joins your squad shortly after the demise of Jenkins on Eden Prime. Because she is a Soldier, Ashley makes a good choice as a member of your squad if you're looking for extra firepower during combat. She is also one of two possible romance options if you're playing a male Commander Shepard.