Ellis entered active military duty in September 1941 as an aviation cadet at Maxwell Field, Alabama.

During World War II, Ellis served with the 3rd Bombardment Group in Australia, New Guinea, and the Philippines, and flew more than 200 combat missions in the Western Pacific area.

In April 1945, Ellis was assigned as deputy chief of staff, United States Far East Air Forces, in the Philippine Islands and Japan.

He requested release from active duty, became a member of the Air Force Reserve and entered Dickinson School of Law in 1946.

From January 1956 to May 1958, Ellis was deputy chief of staff, operations, Headquarters Nineteenth Air Force, Foster AFB, Texas.

He assumed command of 9th Air Force with headquarters at Shaw AFB, South Carolina, in September 1969.

Ellis was promoted to general in 1973 on November 1 (with date of rank September 30), and retired from active duty at age 62 on August 1, 1981.