William Stewart Simkins, lawyer and teacher, was born in Edgefield, South Carolina, on August 25, 1842, the son of Eldred James and Pattie Simkins. He entered the Citadel, the South Carolina military academy, in 1856 and is said to have participated in the firing on Fort Sumter in April 1861. He was commissioned a first lieutenant of artillery in the Confederate Army and served throughout the Civil War. Simkins surrendered as a colonel in the army of Joseph E. Johnston in North Carolina in 1865. Soon after the war he went to Monticello, Florida, where he and his brother Eldred J. Simkins organized the Florida Ku Klux Klan. Simkins was admitted to the bar in 1870, moved to Texas in 1873, and practiced law at Corsicana until 1885, when he and his brother began a practice in Dallas. In the summer of 1899 Simkins joined the law faculty of the University of Texas and began a thirty-year career as the most colorful character ever connected with the law school. Peregrinus, the symbol of the law school, came from a Simkins lecture, and he was often referred to as "Old Peregrinoos." First-year law students were known as "Simkins's Jackasses," and the term J.A. thereafter designated them. Simkins's long white hair, his love of applause, his encounter with Carry Nation in 1903, and his tobacco-all became a part of university tradition. He remained in many ways an unrepentent Confederate, delivering an annual lecture at Thanksgiving in which he criticized the Carpetbaggers, defended the South, and told stories about racist exploits during Reconstruction in Florida. Simkin's publications became standard textbooks, not only in Texas but in other law schools; they included Equity as Applied in the State and Federal Courts of Texas (1903), Contracts and Sales (1905), Administration of Estates in Texas (1908), A Federal Suit in Equity (1909), A Federal Suit at Law (1912), and Title by Limitations in Texas (1924). The University of the South, Sewanee, Tennessee, conferred an honorary doctorate of civil law upon Simkins in 1913. Simkins married Lizzie Ware on February 10, 1870; they had five children. Simkins was a member of the State Bar of Texas and the American Bar Association; he was also a Mason and a member of the Episcopalian Church. He became professor emeritus in 1923, but continued to lecture once a week until his death in Austin on February 27, 1929. He was buried in Greenwood Cemetery, Dallas. During the last years of his life and in his will Simkins gave portions of his private law library to the university.
In 2010, Simkins's historical reputation as a founder of the Klan in Florida led to a demand that his name be removed from a dormitory called Simkins Hall since the early 1950s. The University of Texas responded in July, changing "Simkins Hall" to "Creekside Residence Hall." The university also removed the name of Simkins's brother, Eldred J. Simkins, a member of the UT Board of Trustees from 1882–1893, from a nearby green space.