Biskup was ordained to the priesthood in Rome by Cardinal Francesco Marchetti Selvaggiani for the Archdiocese of Dubuque on March 19, 1937.

[1] Biskup took up graduate studies in the fine arts at the University of Iowa while serving as the administrator of Holy Trinity Parish in Walford.

Biskup became a faculty member in 1939 of Loras College, where he founded the art department and served as artist in residence.

Again returning to Iowa, he was named pastor of St. Joseph's Parish in Key West and chancellor of the archdiocese in 1951.

[5][2] In addition to his episcopal duties, Biskup served as pastor of the Church of the Nativity Parish in Dubuque from 1958 to 1965.

Biskup was named by Pope Paul VI as the fifth bishop of the Diocese of Des Moines on February 3, 1965.

He was formally received into the archdiocese at Saints Peter and Paul Cathedral on October 10, 1967, and also served as pastor of Holy Cross Parish in Indianapolis.