Frederick was born on September 16, 1883 in Summit, New Jersey, the only son of Jay Humphreys and Fannie Brush. He attended the Pennsylvania Military College, and won an appointment from New York to the United States Military Academy at West Point, New York. He was made Cadet Captain, he lettered in fencing, and was the top eighth student of seventy-eight in the West Point Class of 1906. After graduation and commissioning, he was assigned to the Army Corps of Engineers and sent to Fort Riley, Kansas where he worked in bridge construction. 2nd Lt. Humphreys deployed to Cuba during the Pacification Expedition, and a year later, returned to attend the Engineer Officer Basic Course.