He taught school seven years and then studied law.
He was admitted to the bar in 1886. Johnson graduated from the University of Michigan Law School at Ann Arbor in 1887 and practiced his profession in Ironton, Ohio. He served as the prosecuting attorney of Lawrence County in 1889.
Johnson was elected as a Republican to the Sixty-first Congress (March 4, 1909–March 3, 1911).
He was renominated without opposition in 1910, but declined to accept. He resumed the practice of law in Ironton.
He also engaged in banking and was financially interested in various manufacturing concerns. Johnson served as president of the Ohio State Bar Association in 1933.
He died in Ironton on June 11, 1938, and was interred in Woodland Cemetery.
Member 61st Congress (1909-1911), 10th Ohio District
Married Dora B. Ricketts, October 16, 1890.