Demetrius Willis was born on January 14, 1825, in Florence, Lauderdale County, Alabama. He was the eldest of five children who were orphans when Demetrius are 11 years old. Being raised by various aunts and uncles, Demetrius eventually immigrated to Texas and was a citizen of the Republic of Texas. Demetrius lived and fought under three different flags defending the same homestead in Livingston, Texas, under the Republic of Texas flag for independence from Mexico, under the 26 star US flag, defending the Rio Grande as the southern border of the state of Texas with Mexico, and under the Trans-Mississippi Confederate flag defending against external aggression, this time from the North.

He was a state legislator in the 9th Texas Legislature, immediately prior to the War Between the States, as well as during the war, in special session as a state legislator under the CSA. As a state representative prior to the war, he actively opposed secession from the Union, but when he was overruled by those who supported secession, he held greater loyalty to the State of Texas than to the Union. When Texas seceded, Demetrius Willis enlisted on January 24, 1863, at Concord, Texas, as a private, Company C, 1st Infantry Regiment, Texas State Troops, led by Captain W. T. Nettles, and stationed at Camp Gentry. From February 2, to March 6, 1863, Demetrius Willis was granted leave from military duties for an extra session of the CSA state legislature at the request of Governor Frank R. Lubbock. He reenlisted in August of 1863 in the Texas State Troops, stationed at Camp Woods, West Liberty, Texas. In January of 1864, he reenlisted as private, Company C, 20th Texas Infantry, Elmore´s Regiment. He was appointed Clerk for the General Court Martial, Galveston, Texas. He served in that capacity until the end of the war.

In civilian life, Demetrius was owner/operator of a Dry Good Store in Livingston, Texas. He was an active Mason and Worshipful Master of AF&AM Trinity Lodge #14. Demetrius was an active member and officer of a debating club known as the Lyceum Society.

Demetrius Willis died of tuberculosis in Livingston, Texas on August 12, 1872. He is buried at Old City Cemetery, Livingston, Texas. His widow, Anna B. Willis was awarded a Confederate veteran widow’s pension, on 17 March 1887.