Henry Harrison Barnard fought for the Union Army in the Civil War from 1861 to 1864. Following his discharge, he spent time in the South, but eventually settled in Oberlin for the remainder of his life where he operated a grocery business. Barnard was born to Josiah Wood and Sylvia L. Dickenson Barnard in Ludlow, Vermont, on 10 August 1840. He was the youngest of three children including Abby Barnard McRoberts and John Alonzo Barnard. At the age of six he moved to Pittsfield, Ohio with his family. Barnard studied in the Preparatory Department of Oberlin College from 1858 to 1861. However, he left Oberlin before he could graduate.

Barnard enlisted in Battery E of the First Ohio Volunteer Light Artillery on 14 August 1861 at the age of 21. As a noncommissioned officer, Barnard served in the Army of the Cumberland, in the campaigns against the Confederate General Bragg, in Kentucky and Tennessee. He was stationed at Camp Chase; Camp Dennison; Camp Andrew Jackson; Camp Jefferson, Kentucky; Camp Mihalolya, Tennessee; and Marfreesboro. Barnard was taken prisoner at Stone River and confined in Castle Thunder and the Libby prison. After the Union coordinated a prisoner exchange for him, Barnard rejoined his battery until they were mustered out against Columbus, Georgia in 1864. Barnard was finally discharged on 1 September 1864.

After his discharge, Barnard traveled to Cuba Station, Alabama, where he worked as an overseer on a plantation rented by Stephen W. Dorsey in 1865. The following year, he received a commission from Acting Postmaster General Alexander Randall to be postmaster of Cuba Station. Barnard served in this capacity until 1867. Barnard recorded his experiences in the South in an article in the Oberlin News of 16 February 1910 entitled "Story of the South Just after the War."

In 1870, Barnard returned north to Oberlin, Ohio, where he remained for the rest of his life. He opened a grocery store in 1887 and kept the business for twenty-five years. Politically, Barnard was a progressive Republican; he was elected as a delegate to the county conventions of 1888 and 1900. Barnard was also a candidate opposing Judge John W. Steele for the postmastership of Oberlin in 1897, but he was not appointed. He often served as a tax assessor and was the chairman of the Lorain County Soldier's Relief Committee for many years. In addition, Barnard was a charter member of the local Henry Lincoln Post of the G.A.R., where he twice served as commander.

Barnard married Clarissa Gale Pomeroy (OC 1861-2, 1844-1933), a friend with whom he had much correspondence during the war, on 30 March 1872. They had two sons, Ralph Pomeroy Barnard (OC 1890-94, 1873-1939) and John Earl Barnard (PhB 1898, 1875-1949). Henry Barnard died of a stroke of apoplexy in Dr. John E. Barnard's office in Oberlin, Ohio on 12 February 1912.