William M. Carper, soldier and physician of the Republic of Texas, was born in Virginia and apparently traveled to Texas because he had been promised a commission in the cavalry, but on April 10, 1836, acting secretary of war David Thomas appointed him a regimental surgeon. Thomas, in a letter to Sam Houston, described Carper as "a gentleman of fine address." At the battle of San Jacinto Carper served as surgeon of Lt. Col. Henry Millard's First Regiment of Regular Infantry. For his military service from March 9, 1836, through June 8, 1837, Carper was issued a bounty warrant for 1,280 acres that he sold to Governor Henry Smith for $250.
After the war he located his practice in Houston and was apparently appointed chief of surgeons at the city hospital. On May 28, 1839, he married Sarah Ann Minerva Ward of Houston. That same week he was elected president of the Houston Medical and Surgical Society. On September 23 he was elected to the board of the Houston Post Oak Jockey Club; George Washington Hockley was its president, and Sidney Sherman was first vice president. Carper finished third in a four-man race for mayor of Houston in 1841. After only two years of marriage his wife died, on May 16, 1841, at the age of nineteen. In 1850 Carper was living in the Tremont House, Houston, also the residence of his friend Hockley, with a Mrs. Carper, age twenty-four, of Alabama. At the same time he was maintaining a residence in the Rio Grande valley (where he owned $10,000 worth of real estate) with Mary J. D. Carper, age twenty, from Ohio, and a six-month-old orphan named J. W. Crocket.
Carper and Hugh McLeod were the two Democratic nominees from Galveston for the first House of Representatives of the state of Texas in 1846. On April 8 of that year Carper became a cofounder of the Grand Lodge of the International Order of Odd Fellows in Texas. In 1848 he was elected charter treasurer of the Medical and Surgical Society of Galveston. Pat Ireland Nixon reported Carper to be in ill health and nearly blind in Brazoria in 1859, so the report of his death in 1847 by Sam Houston Dixon and Lewis W. Kemp is in error.