[1] He served as prefect of studies in the novitiate in Woodhall House, Edinburgh 1963–1966 and after a further period at Sacred Heart, was seconded as spiritual director to the Beda College, Rome (1976–1980).
During the 1980s, Father Quinn frequently acted as a locum priest to the parish of St Joachims, Wick, Caithness., Scotland.
[2] In the Secretariat for Promoting Christian Unity, he was observer at the General Assembly of the World Alliance of Reformed Churches at Frankfurt in 1964, was consultor to the Secretariat 1968–1973, and was consultant at the World Council of Churches Faith and Order meeting at Leuven, Belgium, in 1972 and at the fourth session of the SPCU/WARC dialogues at Zeist, the Netherlands, in 1973.
He was a translator and consultant to the Catholic Church's International Commission on English in the Liturgy (ICEL) from 1969 and was a member of its advisory committee from 1972 to 1976.
[3] In the 1960s Quinn was vice postulator for the cause for the canonisation of John Ogilvie SJ, Scotland's only post-reformation and only Jesuit saint.