His eldest brother Thomas Francis Marshall (1801–1864) served in the Kentucky legislature and U.S. House of Representatives in 1841–1843 (before their mother's death).

Another brother, William Louis Marshall (1803–1879) became a major with the Maryland Volunteers during the American Civil War but survived the conflict and moved to California where he later died.

by the 1850 census, he was living in a boarding house in Jessamine County and characterized himself as a "mail contractor.

"[2] Dr. Marshall then moved to Missouri, but returned to Kentucky and settled in Fayette County where he resumed his medical practice as well as farmed.

Marshall died near East Hickman, Fayette County, Kentucky in 1884 and was interred at Lexington Cemetery, as would be his son Louis decades later.