William Louis Barker, son of William O. and Julia (Crane) Barker, was born in Upshur County, Texas, on July 2, 1852. He studied medicine in his father's office and graduated from the medical department of the University of Louisiana in March 1874. He married Mollie (Mary) F. Barnes in October 1874 and, in 1879, moved to Longview, where he practiced medicine and ran a drugstore. He moved to Waco in 1882, was city health officer there in 1885, and became division surgeon for the St. Louis and Southwestern Railway. Dr. Barker was superintendent of the Southwestern Insane Asylum (later the San Antonio State Hospital) from 1891 to 1895. He was a member of the San Antonio City Council from 1898 to 1904. He was reappointed superintendent of the asylum in 1907 and served until 1909.