He was created Cardinal Deacon of S. Giorgio in Velabro by Pope John XXIII in the consistory of 15 December 1958. Resigning as Dean on 18 December that year, Jullien was appointed Titular Archbishop of Corone by Pope John on 5 April 1962.
Cardinal Deacon Jullien was appointed by Pope John XXIII in a special ceremony on 15 December 1958. He relinquished his role as Dean on 18 December the same year and later became Titular Archbishop of Corone under Pope John's guidance on 5 April 1962.