Osceola Adolphus Thompson was born around 1837 in Maine to Robert and Nancy Thompson. His father was a farmer and clerk who owned $500 of personal property by 1860. The family lived in Hope, Maine, until the 1850s, when they moved to Providence, Rhode Island. By 1860, he was working as a carpenter.
He enlisted in the Union army on August 21, 1861, and he mustered in as a sergeant in Battery E of the 3rd Rhode Island Heavy Artillery. He was promoted to 2nd lieutenant in July 1862, to 1st lieutenant in January 1863, and to captain in March 1864. He mustered out on April 26, 1864.
He joined the Regular Army after the war, becoming a 1st lieutenant in the 13th United States Infantry in 1867. He married Gertrude Beveridge on December 6, 1871. He died of smallpox in Newport, Kentucky, on January 8, 1873.