Michael was Dean of the Faculty of Law before being elected to the Senate of the Australian Parliament where he served from 1978 to 1993. He chaired numerous committees including the Constitutional and Legal Affairs Committee. He was Federal Minister for Justice 1987 to 1993. He was Ambassador to The Hague and the Holy See 1993-96. He is an Honorary Professor at UTAS where he lectures in International Humanitarian Law.
He is an Officer of the Order of Australia and was ordained a priest in the Roman Catholic Church in May 2000.In 2010 he was appointed inaugural Parliamentary Standards Commissioner under the Tasmanian Integrity Commission Act 2009.