Ransom Foss was born around October 1833 in Lake County, Ohio, to James and Elizabeth Foss. His father was a farmer who owned $1,300 of real estate and $340 of personal property by 1860. The family lived in Painesville, Ohio, until the 1850s, when they moved to Prophetstown, Illinois. By 1860, he was working as a farm laborer.
He enlisted in the Union army on September 7, 1861, and he mustered in as a private in Company B of the 34th Illinois Infantry. According to his service records, he was 5 feet, 10 ½ inches tall, with dark hair and blue eyes. The regiment took part in the Battle of Shiloh, the Battle of Perryville, the Battle of Stones River, the Atlanta campaign, the March to the Sea, and the Carolinas campaign. He eventually earned a promotion to sergeant, and he mustered out on July 12, 1865.
He settled in Sterling, Illinois, after the war, and by 1870, he was working as a bridge tender. He married a woman named Hattie in the 1870s, and their son George was born around 1873. They moved to Harvey, Kansas, in the 1870s and then to Orleans, Nebraska, in the 1880s. He earned a living as a stonemason. His wife died in 1894, and he died on June 30, 1906, in Grand Island, Nebraska, “after suffering a long time of general debility.”