Robert Bentham Boylston was born on November 27, 1822, in Charleston, South Carolina. He enrolled at South Carolina College in the late 1830s, and a classmate described him as “bright, quick, [and] studious.” He graduated around 1841, and he earned a living as a lawyer in Winnsboro, South Carolina. He married Susan Cloud, and they had at least four children: William, born around 1850; Robert, born around 1852; Henry, born around 1856; and Susan, born around 1859; He was elected to the state legislature in 1852, and he served for several terms. He served on the judiciary committee, and he supported railroad construction and education. By 1860, he owned $12,000 of real estate and $58,000 of personal property.
In April 1861, he served as a commissary general on General P. G. T. Beauregard’ staff. Asthma rendered him “disabled” for active service, but in November 1863, he received an appointment as an “enrolling officer for conscripts.” In November 1864, he received a promotion to colonel and an assignment as a military court judge. Around the same time, he was apparently reelected to the state legislature, and he served as speaker of the house. He died in Winnsboro “after a painful illness” on September 4, 1865.