Brian has served as a deputy prosecutor since 1999, and has been prosecuting crimes in Pierce County since 2000. In his quarter of a century in the criminal justice system, he has prosecuted nearly every type of  crime  from misdemeanor traffic offenses to aggravated murder. Brian currently serves as the team chief of the the High Priority Offender (HPO) unit, which focuses on repeat offenders and the most serious identity thieves. In that position, he has seen firsthand the damage done when courts release  recidivists pending serious felony charges. Prior to HPO, Brian served as Team Chief of the General Crimes Trial Team, as well as in the Gang Unit, the Burglary Unit, the Special Assault Unit, the Drug Unit, Domestic Violence Unit, and the Misdemeanor Division. He also has prior experience managing the Juvenile Division of the Cowlitz County Prosecuting Attorney's Office.

Brian served five years in the Pierce County Prosecutor's Office Appellate Division, as well. In that role, he was one of two prosecutors in the state designated by the Washington Association of Prosecuting Attorneys (WAPA) as an appellate resource attorney. As such, he provided trial and appellate advice to prosecutor’s offices throughout Washington, and appeared on their behalf in the Washington State Supreme Court on issues of statewide significance. Brian has also worked on the civil side of law. He has defended the County against civil lawsuits in both Pierce County and federal courts, and served as an assistant advisor to the Sheriff's Department.

Brian continues to serve as an Army Reserve Judge Advocate. In that role, he has among other things, provided legal assistance to service members and retirees, served as a military prosecutor, or Trial Counsel, worked as an S1 (human resources officer), Public Affairs Officer, and advised commanders on  a broad range of matters from investigations to military justice, administrative, fiscal, and operational law. He has had responsibility for subordinates and millions of dollars worth of facilities and equipment, and served as a Field Screening Officer involved in recruiting. (Brian Wasankari is a member of the U.S. Army Reserve. Use of his military rank, job titles, and photograph(s) in uniform does not imply endorsement by the U.S. Army Reserve, the Department of the Army, or the Department of Defense.)

Washington State Bar Association; Tacoma-Pierce County Bar Association; Bar of the U.S. District Court for the Western District of Washington; Bar of the U.S. Court of Appeals for the 9th Circuit; Bar of the United States Supreme Court; Washington State Bar Association Criminal Law Section; Washington State Bar Association Legal Assistance to Military Personnel Section

Brian has volunteered in his community as an elementary school tutor through Read 2 Me (formerly Werlin Reading), with the Pierce County Minority Bar Association Youth & Law Community Forum, and with the YMCA State High School Mock Trial Championship, among other activities.

He has participated in outreach throughout his time in the prosecutor's office, including -teaching Continuing Legal Education classes both within the office and at statewide events; -assisting in training at the Washington State Basic Law Enforcement Academy; and -completing the Pierce County Sheriff’s Department basic defensive tactics course. He has won the office's Outstanding Trial Attorney Award and the 2022 Pierce County Sheriff’s Department Deputy Prosecutor of the Year award.