Immediately after high school Long debuted onscreen as Claudette Colbert's son in Tomorrow Is Forever (1946). He played juvenile supporting roles in a number of A-movies, including the first three Ma and Pa Kettle comedies. Later he played lead roles in second features. He starred in the TV series Bourbon Street Beat, 77 Sunset Strip, The Big Valley, and Nanny and the Professor, and had a supporting role in Maverick. His first wife was actress Suzan Ball, who died at age 22 in 1955; his second wife was actress Mara Corday, whom he married in 1957. He died at age 47 of a heart ailment.