He served as the head football coach at Daniel Baker College in Brownwood, Texas from 1921 to 1923.

Gilfillan played football at Texas A&M University from 1914 to 1916.

[1] Gilfillan served in the United States Marine Corps in World War I and World War II, reaching the rank of lieutenant colonel.

A native of St. Johnsbury, Vermont, he was wounded in action during World War I.

[2] Gilfillan worked in the brick business and was a resident of Tyler, Texas for 28 years, until his death there on May 24, 1954.