Gilliland was born on July 10, 1909, in El Reno, Oklahoma and moved with his family to Little Rock, Arkansas in 1918.
from MIT in 1933 under the direction of Thomas Kilgore Sherwood for work on a wetted-wall column technique used in mass-transfer.
He consulted extensively with Exxon, Merck, Goodyear, General Electric, and Nestle and also served as the President and CEO of Ionics, Inc. between 1946 and 1971.
He was the Assistant Rubber Director for the War Production Board between 1942 and 1944, Deputy Chief of the Chemical Engineering division of the National Defense Research Committee, Deputy Chairman of the Guided Missiles Committee on the Joint Chiefs of Staff, and the President's Science Advisory Committee under Presidents Kennedy and Johnson.
Gilliland married Ann Frances Miller in 1938 and had one daughter, Gail.