Colonel Trevor J. Walker enlisted into the New Zealand Army in January 1991 and commenced officer training at the Officer Cadet School Waiouru. He graduated in December 1991 into the Royal New Zealand Infantry Regiment in the rank of Second Lieutenant.

Colonel Walker has completed a number of postings within the Royal New Zealand Infantry Regiment including Platoon Commander, Company Second in Command and Officer Commanding Bravo Company 2nd/1st Battalion.

Colonel Walker has held posts as the Aide de Camp to the Chief of Army, Senior Instructor Field Wing Officer Cadet School Waiouru, Chief Instructor Tactical School Waiouru, and has also held appointments within Army National Recruiting Office and Military Career Management. Colonel Walker assumed the post of Commandant of the Officer Cadet School (NZ) in December 2010 after completing the post of New Zealand Directing Staff at the Malaysian Staff College. Colonel Walker was the Army Inspector General on return from the US Marine Corps War College.

Colonel Walker has deployed to Afghanistan to the NATO Division Headquarters as the J3 Watchkeeper and to Egypt with the New Zealand Contingent Multinational Force, Sinai. Colonel Walker deployed to Kuwait as part of Operation Inherent Resolve in 2014 and to Iraq as the J7 on the Combined Joint Force Land Component Command Headquarters for six months in 2015.

Colonel Walker served as the Personal Staff Officer to the Chief of New Zealand Defence Force prior to commencing his current role as Deputy Commander - Interoperability of the US 25th Infantry Division.

Colonel Walker is a graduate of the UK Command and Staff College, US Marine Corps War College, and holds a Bachelors Degree in Defence Studies and Masters Degrees in Strategic Studies.
Colonel Walker has played competitive age group rugby and enjoys most outdoor sports and pursuits, including competing in the Around-Taupo Cycle race and the Speights Coast to Coast.

Colonel Walker is married and has three children.