Pope Paul VI created him Cardinal Priest of S. Chiara a Vigna Clara in the consistory of 28 April 1969, and therefore the first resident cardinal in Scotland since David Beaton, over four centuries earlier. In 1977 Gray became the first cardinal to address the Church of Scotland's General Assembly. He once served as President of the Bishops' Conference of Scotland, and was one of the cardinal electors in the conclaves of August and October 1978, which selected Popes John Paul I and John Paul II respectively. In 1978, he voiced strong opinions regarding the birth of Louise Brown, the first child to be successfully born from in vitro fertilisation, saying: "I have grave misgivings about the possible implications and consequences for the future." During John Paul II's 1982 visit to the United Kingdom, he officially welcomed the Pope upon his arrival in Scotland.