Dignam was born on Lord Howe Island.
[3] He was best known for one of his early roles, that of Brother Francine in Fred Schepisi's The Devil's Playground (1976).
He played Pontius Pilate in the Australian production of Jesus Christ Superstar in 1972–73, and appears on the original Australian cast recording.
[5] During 1980, Dignam was part of A Shakespeare Company,[6] funded by a one-off grant from the Australia Council, and worked with actors Ruth Cracknell, Ron Haddrick and others on two texts for six months and then presented them at the Seymour Centre.
Dignam died of a heart attack on 9 May 2020, in Sydney at the age of 80.