 He then came to the United States as a permanent resident in 1952, and became a naturalized citizen in 1960.Tavard accepted a teaching position at Mount Mercy College in Pittsburgh, where he would teach for six years.During his tenure at Mount Mercy College, Pope John XXIII named Tavard a peritus conciliaris at Vatican II, where he also served as a consultant to the Secretariat for the Promotion of Christian Unity.