Born in Maitland, Walsh attended Manly Boys' High School and Sydney Technical College before receiving a Bachelor of Arts form the University of Newcastle and a Diploma of Education from the Newcastle College of Advanced Education.
He served as a fighter pilot in the RAAF 1962–70, and was then a teacher at Newcastle and Maitland Technical College.
[1] In 1981, when the local state Liberal MP for Maitland resigned, Walsh was selected as the Labor candidate to contest the by-election.
However, the 1981 redistribution made Maitland a solid Labor seat and Walsh easily defeated Toms in the state election later the same year.
He was nearly defeated in 1988, surviving by 444 votes, and when the 1991 redistribution gave the seat a 7.4% Liberal margin, Walsh retired from politics.