Frederick Newman Knapp was born in Boston, Massachusetts, on November 19, 1821, the son of Jacob N. and Louisa Knapp. He had at least one brother, Francis. The Knapp family moved to Walpole, New Hampshire, when Frederick was a young child. He received a bachelor's degree from Harvard in 1843 and a divinity degree from Harvard Divinity School a few years later. He then became the preacher of the Congregational church in Brookline, Massachusetts, where he served until 1855, when he temporarily retired to Walpole because of an illness. During the Civil War, he served with the United States Sanitary Commission's Special Relief Service in Washington, D. C. After the war, he worked as a schoolteacher and schoolmaster in New Jersey and Massachusetts. He married Lucia Bradford on May 9, 1855, and they had four children: Louisa, Frederick, Sarah, and Maria. Frederick Newman Knapp died on January 12, 1889.