Mary Duddy is known for The Autopsy of Jane Doe (2016), Screen One (1985) and Coronation Street (1960).

Mary Duddy appeared on Coronation Street in two roles: firstly as orphanage official Mrs Donovan in February 1961 and she returned to the programme in the recurring role of Elliston's Raincoat Factory worker Audrey Plant between June 1961 and July 1962.

Her other television credits include The Budds of Paragon Row, Z Cars, Marked Personal, Within These Walls, Doctors' Dilemmas, Cover Her Face and Spatz. On the bigger screen, she appeared in the films The March and The Autopsy of Jane Doe.

On stage, she has appeared in productions of Twelfth Night, Macbeth, Hedda Gabler, Pygmalion, A Midsummer Night's Dream, The Family Reunion, A Warwickshire Testimony and Lady Windermere's Fan.