Rear Adm. Williamson is a native of Levittown, Pennsylvania. 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 on USS Estocin (FFG 15), USS Vandegrift (FFG 48), and as executive officer of USS Vicksburg (CG 69). He commanded USS Thunderbolt (PC 12), USS Porter (DDG 78), and Destroyer Squadron 2. He also served as chief of staff, Carrier Strike Group 2/Theodore Roosevelt Strike Group; and as chief of staff, Naval Striking and Support Forces NATO.
Ashore, he served as graduate education and service college placement officer; as future schedules officer on the staff of Commander, Naval Surface Forces Atlantic; as lead staff analyst in the Office of Program Analysis and Evaluation (PA&E) for Cost of War (COW) Supplemental on the staff of the Secretary of Defense; as an executive assistant in OPNAV N81 (Naval Assessments) and OPNAV N86 (Surface Warfare) to the deputy commander, U.S. Fleet Forces Command.
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 Defense Superior Service Medal, Legion of Merit (5 awards), Defense Meritorious Service Medal, Meritorious Service Medal (2 awards), Navy and Marine Corps Commendation Medal (4 awards), Navy and Marine Corps Achievement Medal, and various campaign, unit, and service awards.
Williamson has served as the commander, NATO Standing Maritime Group 2 since July 2014.