Ms. Campion worked for a decade as a journalist before joining Mr. Joyce’s re-election campaign as a staff member in 2016. They began their affair late that year.
“As far as I see it, everyone else is making money out of Sebastian, except for Sebastian,” Ms. Campion said, explaining that the money from the interview was going into a trust for their son.
Viewers criticized the interview for failing to address key questions, including why the pair was living in a rent-free apartment donated by a supporter of Mr. Joyce, and whether Mr. Joyce was trying to obfuscate his affair by securing Ms. Campion a job in another political department.
The paid interview was the latest in a string of controversies involving Mr. Joyce, who last year was forced to resign his seat after revelations that he held dual citizenship in Australia and New Zealand. He won back his seat in a subsequent election.
The news of Mr. Joyce’s and Ms. Campion’s affair led the prime minister to update parliamentary standards to rule that sitting ministers may not have sexual relations with their staff members.
Ratings for the “Sunday Night” program suggested that the Australian public may have seen enough of Mr. Joyce’s private life. The heavily promoted interview drew lower ratings than local editions of “MasterChef” and “The Voice,” as well as “Mystery Road,” an outback neo-noir series.