Born in Kensington, London, he was the oldest of eleven children of James Caer Greenwood, a coach builder, and his wife, Mary Ann, née Fish. He and two brothers – James and Charles, gained reputations as journalists. Frederick started life in a printing house, but at an early age began to write in periodicals. In 1853 he contributed a sketch of Napoleon III to a volume called "The Napoleon Dynasty" (2nd ed., 1855). He also wrote several novels: "The Loves of an Apothecary" (1854), "The Path of Roses" (1859) and (with his brother James) "Under a Cloud" (1860).