He attended the Virginia Military Institute on the four-year Navy ROTC Scholarship program, graduating in 1981 with a BS in Civil Engineering. He was commissioned a second lieutenant in the United States Marine Corps. After completing The Basic School and the U.S. Army Field Artillery Officer Basic Course, his first operational assignment was with the 7th Marine Amphibious Brigade, 29 Palms, California. In 1984 he transferred to the 12th Marine Corps District for duty as the Officer Selection Officer, Seattle. While a captain, he served in the 4th Marine Division as Executive Officer, Company "B," 4th Tank Battalion in Yakama, Washington, and as Commanding Officer, Battery "H", 3rd Battalion, 14th Marines, Richmond, Virginia. During his command of Battery H, the unit mobilized and attached to 1st Battalion, 11th Marines, 1st Marine Division, I Marine Expeditionary Force, and conducted combat operations during Operation Desert Shield and Operation Desert Storm in Saudi Arabia and Kuwait. Promoted to major in 1993, he joined the 4th Civil Affairs Group as a Civil Affairs Team Commander, were he supported the 24th Marine Expeditionary Unit and the U.S. Atlantic Command Joint Overseas Training Program in Jamaica and the Bahamas. In 1996, Brier was assigned as the Operations Officer and Executive Officer, 3rd Battalion, 14th Marines, and deployed the battalion to northern Norway for NATO Exercises Strong Resolve 98. Promotion to lieutenant colonel in 1998, he transferred to the II MEF Augmentation Command Element and served as II Marine Expeditionary Force Current Operations Fires Officer for a second winter deployment to Norway for NATO Exercise Battle Griffin 99. In 2000, Brier assumed command of 3rd Battalion, 14th Marines. In 2002, he transferred to the U.S. Joint Forces Command for duty as Chief, Civil Affairs Branch, Joint Warfighting Center.
Promoted to colonel in 2003, he served at the Pentagon as a Marine Corps Service Planner, Joint Staff Branch, where he assisted the Commandant of the Marine Corps in preparing for meetings of the Joint Chiefs of Staff. In July 2004, he graduated from the International Joint Operations Planning Course at HMS Dryad. In February 2005, Brier was selected to build and command the 6th Civil Affairs Group, a provisional unit commissioned for service in Operation Iraqi Freedom. The 6th CAG provided civil affairs support for the 2d Marine Division and Multi-National Force West’s counterinsurgency operations in al-Anbar province during Operations Sayeed II, Steel Curtain, Liberity Express and Patriot Shield II and for two major national elections: the 15 Nov 2005 National Constitutional Referendum and the 15 December 2006 Parliament Elections. In 2007, Brier was assigned as Chief of Staff, 2d Marine Division. In 2008, he deployed to Afghanistan and served as Officer-in-Charge, US Marine Forces Central Command Coordination Element- Afghanistan; and MARCENT Liaison Officer to CJTF-101, Combined Security Assistance Force-Afghanistan, and NATO’s International Security Assistance Force. He held this position until selected by the Commandant of the Marine Corps to redeploy to Guam to establishing a permanent Marine Liaison Office to coordinate issues involving the move of Marine personnel and facilities from Okinawa to the island. He assist the Governor of Guam in developing the island’s civil infrastructure plans to support an estimated thirty percent increase in population caused by the relocation. He reported to Guam in July 2008 and promoted to Brigadier General in 2009. As a Brigadier General, Brier commanded U.S. Marine Corps Forces Europe and U.S. Marine Corps Forces Africa. In 2011, he served at sea as the Deputy Commander of the Joint Force Maritime Component Command, a naval task force which included the USS KearsargeExpeditionary Strike Group and the 26th Marine Expeditionary Unit, and conducted contingency operations in Libya and the Mediterranean Sea. He was promoted to Major General in 2013 while serving as the Vice Commander, U.S. Marine Corps Forces Command, Norfolk, Virginia. As a Major General, Brier served at the Pentagon as the Assistant Deputy Commandant for Plans, Policies, and Operations, before taking command of the 20,000 Marines and sailors of the 4th Marine Division. On July 16, 2015, Battery M, 3rd Battalion, 14 Marines, 4th Marine Division was attacked by a domestic terrorist in Chattanooga. In 2016, he returned from his final tour in Afghanistan where he had served as the Deputy Commander for Civil Outreach and Director of the Advise and Assist Directorate for the 41-nation NATO-led Resolute Support Mission.
