Demetrius Willis, merchant, soldier, and state representative, son of Joshua Willis and Martha (Hall) Willis, was born in Florence, Lauderdale County, Alabama, on January 14, 1825. After the death of his parents in 1836, Willis was taken in by his maternal aunt in Talladega County, Alabama. At some point between 1843 and 1845, he immigrated to Texas to live with an uncle in San Augustine. During the Mexican War, Willis served as a private in Company A of the Second Texas Mounted Volunteers and was present at the capture of Monterrey in September 1846. Following the end of the war, Willis settled in Gonzales, Texas, where he served as city secretary and later as district clerk. He was also president of the Gonzales Lyceum Society and a co-founder of Gonzales College. Willis resigned his clerkship in 1854 and opened a general store. He married Margaret Elizabeth Brown of Missouri in 1849. They had at least five children.
In 1858 Willis moved with his family to Livingston, Polk County, Texas. Here he established himself as a merchant and one of the community’s first storeowners. By 1860 he was worth $35,000 in personal and real estate property. During the Civil War, Willis served Texas and the Confederacy in various capacities. In 1861 he won election as representative for Polk and Liberty counties to the Ninth Texas Legislature. On January 24, 1863, he enlisted as a private in Company C, First Infantry Regiment, Texas State Troops, and served for three months. He reenlisted with this unit, again for three months, in August 1863. At the beginning of January 1864 Willis served with Company E of the Twentieth Texas Infantry Regiment. By the end of that month, however, he left that unit and gained appointment as clerk for a general court martial established in Galveston. He served in this capacity until the general surrender of Texas forces in May 1865. Around this time, Willis returned to Polk County. His wife, Margaret, died in 1865, and he married Anna Brown McKean on May 15, 1866. Willis died from tuberculosis in Livingston on August 12, 1872, and was buried there at Old City Cemetery. He was a Master Mason.