Senior public servant Stephanie Foster will be the new head of the Home Affairs department after the removal of Mike Pezzullo.
Mr Pezzullo was sacked as department head after it was revealed he repeatedly inserted himself into the political process and broke the code of conduct at least 14 times.
Ms Foster had been serving as the acting Home Affairs secretary after Mr Pezzullo was initially stood aside pending an inquiry.
Prime Minister Anthony Albanese said Ms Foster will serve a five-year appointment in a permanent role, which started on Tuesday.
"Ms Foster has well-established relationships across the Australian Public Service and significant policy experience, which make her eminently suitable to the role of secretary," he said.
Previously, Ms Foster has served as associate Home Affairs secretary, and was the deputy secretary of the Department of Prime Minister and Cabinet.
She has also held senior positions in the Australian Public Service Commission, the Department of Infrastructure and the Department of Defence.