Samuel Boyer Davis was born around 1826 in Louisiana. He briefly attended the United States Military Academy, and he served in the Mexican American War. He took part in the Battle of Churubusco and the Battle of Chapultepec, and he was wounded at Molino del Rey. He lived in Texas in the 1850s. He married Mary Clark, and the couple had at least two children. His wife and children, however, died during a yellow fever epidemic in the mid-1850s.
In 1861, he helped organize a mounted battalion, which eventually became the 26th Texas Cavalry. He served as major of the unit. According to one scholar, he was promoted to colonel in 1862, but “members of the regiment protested and claimed the right to elect their own officers.” In response, Davis resigned from the regiment. By March 1865, he was serving as a captain and assistant adjutant general.
He married Rhoda Milby, and the couple had at least seven children: Anna, born around 1869; Maria, born around 1870; Samuel, born around 1872; Edith, born around 1873; Gertie, born around 1874; Ernest, born around 1876; and Harry, born around 1878. The family lived in Galveston, Texas, and he earned a living as a broker and real estate agent. By 1870, he owned $2,500 of real estate and $500 of personal property. He died in New Orleans on December 13, 1885.