William D. Leahy
Stewart was placed on the retired list on 21 December 1861 after serving 63 years in the Navy. His age at the time of his retirement was 83 years, 4 months and 24 days – making him the second oldest officer on active duty in the history of the U.S. Navy (after William D. Leahy). He was promoted to rear admiral on the retired list on 16 July 1862. Stewart holds the all time records for the longest active duty career and longest time holding a single rank on active duty (52 years 10 months).