Reuben Bemis was born on June 5, 1825, in Ohio. He married Mary Jane Rowley on October 7, 1847, and they had at least four children: Helen, born around 1848; Daniel, born around 1849; James, born around 1860; and William, born around 1870. They lived in Milan, Ohio, and Bemis worked as a laborer. By 1850, he owned $200 of real estate. A decade later, he owned $800 of real estate and $300 of personal property.
He enlisted in the Union army on February 29, 1864, and he mustered in as a private in Company B of the 25th Ohio Infantry later that day. The men spent the next year stationed in South Carolina. He remained devoted to the Union, praying in June 1864 that the war would soon end that “our stares [sic] and stripes wave over the land of the brave and the home of the free." Bemis was discharged for disability on May 19, 1865.
Bemis returned to Milan after the war, and he earned a living as a farmer. By 1870, he owned $1,300 of real estate and $900 of personal property. He died on November 23, 1875.