Cornelius B. Campbell was born on October 4, 1818, in Henniker, New Hampshire, to Hezekiah and Rebecca Campbell. His father was a shoemaker. He attended school in Vermont before enrolling at the Oneida Institute in Whitesboro, New York. By the late 1840s, he was working as a Congregational minister.
He moved to Low Moor, Iowa, in the 1850s, and he married Phebe Thomas. By 1860, they owned $750 of real estate and $1,400 of personal property. According to an early biographer, they “made their home one of the stations on the Underground Railroad, receiving, secreting and forwarding fugitive slaves along the line.” He worked closely with fellow conductor George W. Weston, and he helped raise Weston’s two children after Weston and his wife died. He supported the Union war effort, declaring in June 1863 that "'God & Liberty' will triumph & I begin to think sooner than most expect, Copperheadism must go in under."
The family moved to Vineland, New Jersey, in the 1860s, and by 1870, he owned $6,000 of real estate and $500 of personal property. He became a prominent member of the community, and he served as president of the Vineland Historical and Antiquarian Society. He also served as secretary of the local Agricultural and Horticultural Society and secretary of the local Industrial College.
He supported the women’s rights movement, and he helped organize the New Jersey State Woman Suffrage Association. At its first meeting in 1867, he declared that “the friends of woman suffrage should vote for no candidate for civil office who will not publicly pledge himself to be practically in favor of the enfranchisement of woman.” He died on May 6, 1889, in Landis, New Jersey.