Brigadier-General Lockhart enrolled in the Canadian Armed Forces in 1990, graduated from the Collège militaire royal de Saint-Jean (CMR Saint-Jean) and joined the Royal Canadian Regiment. He spent 10 years on Regimental Duty split between Second Battalion in Gagetown and primarily Third Battalion in Petawawa. Twice deployed as a rifle platoon commander in Bosnia, and was later deployed twice to Afghanistan, followed by twice to the greater Middle East. He had the privilege of commanding the Canadian Forces Land Advanced Warfare Centre from 2011 to 2013, guiding the modernization of the Canadian Army’s mountaineering, arctic, pathfinder and parachute training programs. Following a year at US CENTCOM HQ, Brigadier-General Lockhart was appointed Director of Cadets at the Royal Military College of Canada (CMR). In June 2023 he was assigned to his current appointment as Deputy Chief of Staff-Professional Conduct and Culture and was promoted to his current rank on 20 Oct 2023.

As of August 2025 he assumed responsibilities as the Canadian Army’s Chief of Staff Operations.

Brigadier-General Lockhart holds an Honours Degree in Military and Strategic Studies de CMR, and a Masters of Defence Studies from Royal Military College of Canada (RMC) Kingston.

He is married and the couple has two daughters.