In 1840, Wallace participated in the Battle of Plum Creek, and in the Spring of 1842, fought against Mexican General Adrian Woll's invasion of Texas.

Later that year, he volunteered for the Somervell Raid across the Rio Grande River and afterwards, joined a splinter group that was later called the Mier Expedition, to further penetrate into Mexico. However, the group was surrounded and captured by a force ten times their size. Forced into central Mexico, the men were able to escape, but were quickly recaptured and forced to participate in what became known as the “Black Bean Incident.” This was a “lottery,” in which black and white beans were placed in a crock, in a 1 to 10 ratio. Those who drew a black bean were executed, while a white bean meant prison. Wallace was one of the “lucky” ones, drawing a white bean and soon found himself on an 800 mile forced march to the Perote Prison in Vera Cruz. After a petition was signed by a number of U.S. Congressmen, he was released and after his return to Texas, joined in the Mexican-American War. After the war, he commanded a company of Texas Rangers fighting border bandits and Indians on the frontier. When the Civil War erupted, he was still helping to guard the frontier against the Comanche Indians

Somewhere along the line, Wallace was granted a piece of land by the State of Texas, where he ranched along the Medina River. However, in his later years, he was living in Frio County, and when a small village was formed, it was named “Bigfoot,” after Wallace, who had made a legend of himself during his lifetime.

Described as humorous, mellow, and honest, he became a teller of tales, which though sometimes embellished, were extremely popular among his visitors. In 1870, some of these tales were told by biographer, John Duval, in a best selling book called The Adventures of Big Foot Wallace, The Texas Ranger, which further contributed to his reputation as a Texas folk hero.

Wallace died on January 7, 1899, and shortly thereafter the Texas legislature appropriated money for moving his body to the State Cemetery in Austin, Texas.