Edward Mallory ( Cumberland , June 14 1930 - Salisbury , April 4 2007 ) was an American actor . He was most famous for his role as Dr. Bill Horton in Days of our Lives from NBC where he played from 1966 to 1980 . Mallory was married to actress Joyce Bulifant and later with Susanne Zenor , who played Margo Horton in Days of our Lives . Mallory was affiliated with the University of Frostburg [1] . He died at the age of 76 years.