Șușman was born in Măhăceni, Alba County on June 10, 1910, in a family of Greek-Catholic peasants. After graduating with a law degree from the University of Cluj, he joined the Iron Guard. In 1941 he was sentenced to 10 years in prison for his participation in the Legionnaires' rebellion and Bucharest pogrom; however, he escaped capture and fled to the Apuseni Mountains. In 1945, following an agreement between Iron Guard leader Nicolae Petrașcu and Interior Minister Teohari Georgescu which granted Iron Guard members amnesty in exchange for turning in their weapons, Șușman returned to civilian life and practiced law in Ocna Mureș; he did so until May 15, 1948, when the Communist authorities started to arrest ex-members of the Iron Guard and fascist sympathizers. At that time, he and his brother, Gheorghe Șușman, went underground, hiding from the authorities in the area between Turda, Ocna Mureș, Aiud, and Blaj.