 Adamec was born in Bannister, Michigan the son of Michal August Adamec and Alzbeta Eva Ochran Adamec.He attended Michigan State University from 1953 to 1955, and studied for the priesthood at the Pontifical Nepomucene College in Rome and earned a Licentiate in Sacred Theology at the Pontifical Lateran University in 1961.He was ordained by Luigi Cardinal Traglia in the Church of St. Anselm in Rome on July 3, 1960, for the Diocese of Nitra in Slovakia (the former diocese of his parents).