John Paul II created Hickey Cardinal Priest of "Santa Maria Madre del Redentore a Tor Bella Monaca" in the consistory of June 28, 1988. Hickey was, at that point, one of thirteen Americans in the College of Cardinals. That same year, he was invited to lead a retreat for the pope and his household. Within the United States Conference of Catholic Bishops, he served as Chairman of the Committee on Doctrine (1979–81), of the Committee on Human Values (1984–1987), and of the Committee on the Pontifical North American College (1989–1991; 1994–1997).