A special election was called in 1913 to choose Rayner's successor, but Jackson chose not to become a candidate. He served from November 29, 1912, until January 28, 1914, when an elected successor, Blair Lee I, officially qualified for the position.
Following his short tenure in the Senate, Jackson resumed his former business pursuits in the lumber business. Jackson later served as Maryland State treasurer from 1918 to 1920; as president of the Salisbury National Bank; and a director of the Baltimore, Chesapeake & Atlantic Railway Company.