Born in Bradford, Vermont, the son of Hezron George Day, on 8 November 1871,[1] he was appointed to the United States Naval Academy on 19 May 1888 by Congressman William W.

Returning to the United States in 1901, Day was assigned to the Boston Navy Yard[4] and subsequently was Executive Officer of the transport USS Hancock during 1907.

By 1917 he was the Head of the Department of Compasses, Nautical Instruments, and Time Service at the Naval Observatory.

During World War I, in the rank of Captain, he commanded the troop transport USS America, formerly the German liner SS Amerika, and was awarded the Navy Cross for this service.

Promoted to Rear Admiral in 1925, he served first as Commandant of the 15th Naval District, and then as Commander of Light Cruiser Division 2 (Trenton, Milwaukee, Raleigh and Memphis) from June 1927 to April 1928[5][6] and Light Cruiser Division 3 (Richmond, Cincinnati and Marblehead) from April 1928 to July 1929.