Marshall Hilliard was born in Danby, Vermont, on August 27, 1830, one of the eleven children of harness-maker Isaac Hilliard (1797-1870) and his wife, Sarah Hunt (1797-1859). In 1836, the Hilliard family moved to Ashtabula County, Ohio, and settled in the village of Orwell. Isaac learned the trade of harness-making from his father, but in 1852 moved to California, where he worked as a miner, performed tunnel and hydraulic work, and speculated and lent money for profit. In 1863, he returned to Orwell, where he and his brother Frank started a business, for which they went south to buy cotton in December 1863.
Early in 1864, Hilliard was captured and imprisoned by Confederates in Yazoo City, Mississippi, and was eventually transferred to Demopolis, Alabama; Mobile, Alabama; and Meridian, Mississippi. He escaped on July 24, 1864, and returned to Ohio in the fall of that year. From 1867 to 1874, he and his brother-in-law ran a merchandise business, after which Hilliard went into the circus business, for which he acquired a tiger, a lion, an elephant, and 120 horses. In 1867, he married Julia M. Baker, with whom he had one daughter, Zella. Hilliard eventually bought and managed two local hotels, the Orwell House and the Hotel Beechen. He died March 3, 1914.