Promoted to first sergeant in 1998, Sergeant Major Barrett was transferred to 3rd Battalion 4th Marines at Twentynine Palms, serving as the company first sergeant for Company I, Headquarters and Service Company, and Weapons Company.
He was transferred to and deployed to Iraq twice with 2nd Battalion 7th Marines in 2005 and 2007, earning a Bronze Star with valor device on each tour for leadership under fire.