Archbishop Hart told the Royal Commission into Institutional Responses to Child Sexual Abuse that Father Michael Glennon was first convicted and jailed in 1978 but it was not until 1998 that he was laicised.
He was convicted five times on multiple charges and died in jail in January this year.
Archbishop Hart, who was vicar general of the Melbourne diocese before being appointed archbishop in 2001, replacing George Pell, told the hearing it was very difficult before 2001 to get approval from the Vatican to defrock a priest.
“The difficulty would be a serious concentration on procedure,” he said.
“If every I wasn’t dotted and every T crossed in the way that they wanted, then there was a leaning in favour of a priest who might have been accused of something.”