A veteran of the Pancho Villa Expedition and World War I, Hancock went on to serve as Syracuse's corporation counsel from 1926 to 1927.

[4] As a member of the New York National Guard's 1st Cavalry Regiment, Hancock attained the rank of sergeant and served on the Mexican border during the 1916 Pancho Villa Expedition.

[4] During World War I, he served in France with the 104th Machine Gun Battalion, a unit of the 27th Division, and attained the rank of captain as commander of the battalion's Company D.[4] He subsequently served as an assistant to the division's judge advocate, J. Leslie Kincaid.

[5] The 27th Division commander, John F. O'Ryan, cited Hancock for bravery during combat at Jonc de Mer Ridge, near Le Cateau-Cambrésis, France, on October 18, 1918.

[6] During the fighting, Hancock personally conducted front line reconnaissance to determine the best locations to emplace his guns.

[7] While under fire throughout the battle, he maintained liaison with the Infantry units his company supported in order to enable their attack.

[12] In addition to his legal career, Hancock was also involved in civic and charitable endeavors, including serving as president of the Syracuse Music Festival Association.

[4] In 1927, Hancock was a successful Republican candidate in a special election for the United States House of Representatives.

[4] They were the parents of a son, John S. Hancock (1914–2007), a veteran of World War II who pursued a banking career in Syracuse.