 His maternal grandfather Paddy Glynn was a federal government minister, while his sister Maev O'Collins became a professor at the University of Papua New Guinea.O'Collins studied at the University of Melbourne, where he took both a first-class honours baccalaureate degree and a master's degree.He was ordained a Roman Catholic priest in 1963 and went on to earn a Licentiate in Sacred Theology (STL) at Heythrop College, Oxfordshire, in 1967.