Captain Warfield is the staff judge advocate for Marine Corps Activity Guam, where he also serves as a special assistant United States attorney for the District of Guam. He was sworn in as a second lieutenant via the Marine Corps direct commissioning program in 2009. Previously stationed at Camp Pendleton, he served there as a trial counsel and defense counsel. In 2012 he deployed to Helmand province, Afghanistan, to serve as the senior defense counsel for Regional Command (Southwest).