McGrath is probably best known to international audiences for her early performances on Australian television as fair-minded but sarcastic Deputy Governor Colleen “Po Face” Powell in the cult series Prisoner. Initially appearing on-and-off for the first two years on the show, Powell became a leading character in 1981 and McGrath continued the role in that way before leaving the series permanently in 1984.
After this she appeared in guest roles in 1985 episodes of Neighbours and The Flying Doctors. She also appeared in one series of the Australian children’s television show Round The Twist as Matron Gribble. She was also a regular cast member on A Country Practice as Bernice Hudson from 1992 until 1993.
She played the long-running role of Yvonne Von Ryan in television medical drama series All Saints from its debut in 1998. She is the only original cast member to stay with the series until it concluded in late 2009.
Most recently Judith portrayed the role of Mrs Herring lending superb comic relief (Australian Stage) in STC’s acclaimed production of The Secret River, directed by Neil Armfield.