Sexton retired as a rear admiral on 1 October 1940, but remained on active duty because of World War II until his death in 1943.

[10] During World War I, Sexton received a temporary promotion to captain and served on the staff of the commander-in-chief of U.S. naval forces in European waters, earning the Navy Cross.

[5][11] After the war in October 1919, Sexton replaced Rear Admiral Harry S. Knapp as the U.S. naval attaché in London.

[1][5][17] He retired after reaching the age of sixty-four in September 1940, he was then originally slated to be replaced by Rear Admiral John W. Greenslade[18][19] but was then personally asked to stay on by President Franklin D.

In August 1942, he was replaced as chairman by Rear Admiral Arthur J. Hepburn but continued to serve as a member of the General Board.

[21][22] He died at the Naval Medical Center in Bethesda, Maryland on 9 September 1943[1][5] and was interred at Arlington National Cemetery two days later.