She attended Our Lady of Mercy College, Heidelberg and the University of Melbourne, where she received a Bachelor of Arts.

[3] Crennan was a teacher of English literature and was employed by various patent attorneys in New South Wales and Victoria between 1967–1978.

[6] Her final cases included consideration of the legality of the detention of 157 Sri Lankan Tamil asylum seekers at sea in July 2014,[6] under Operation Sovereign Borders.

[7] In January 2008 Crennan was awarded the highest Australian civilian honour, Companion of the Order of Australia (AC), for outstanding service to the law and the judiciary, particularly through leadership and mentoring roles with legal and professional associations, as a contributor to reform, and to the community.

[10] Crennan launched the Peter Steele Poetry Award, a scholarship available to PhD students in the Faculty of Arts at the University of Melbourne, in November 2017.