Rear Adm. (select) Williamson is a native of Levittown, Pa. He is a 1985 graduate of the United States Naval Academy. He received a Master of Science degree in National Security Strategy from the National War College in 2001.

His career as a surface warfare officer includes assignments aboard USS Estocin (FFG 15), USS Vandegrift (FFG 48), and as executive officer in USS Vicksburg (CG 69). He commanded USS Thunderbolt (PC 12), USS Porter (DDG 78), and Destroyer Squadron Two. He also served as chief of staff, Carrier Strike Group Two/Theodore Roosevelt Strike Group.

Ashore, he has served as graduate education and service college placement officer; as future schedules officer on the staff of Commander, Naval Surface Forces Atlantic; and, as an executive assistant in OPNAV N81 (Naval Assessments), and in OPNAV N86 (Surface Warfare).

Williamson participated in Operations Desert Shield and Desert Storm, and has conducted numerous operational exercises and missions in Europe, Africa, and South America.

His decorations include the Legion of Merit, Defense Meritorious Service Medal, Meritorious Service Medal, Navy and Marine Corps Commendation Medal, Navy and Marine Corps Achievement Medal, and various campaign, unit, and service awards.

Williamson has served as the executive assistant to the Deputy Commander, U.S. Fleet Forces Command since August of 2011.