Rachel Nobel has been named the new head of the Australian Cyber Security Centre, taking on the role of protecting government cyber security.
Ms Noble will replace Alastair MacGibbon, who announced he was stepping down from the role in May.
She is currently deputy secretary of the executive group at the Department of Home Affairs, where intelligence services fall under the responsibility.
In an announcement to staff at the Australian Signals Directorate, director-general Mike Burgess said Ms Noble was "ideally qualified" to confront the cyber threat.
"I'm particularly impressed by Rachel's leadership qualities, which were so well displayed when she and I worked together previously to improve cyber policy across government," Mr Burgess said.
Ms Noble said, "I am really looking forward to returning to ASD to work with Mike and his team.
"I have always enjoyed the work of ASD and this will be the third time in my career that I have worked there. I'm delighted to be reconnecting with some of my old colleagues and making new ones too."
Ms Noble, who has been awarded the public service medal, has a long public service career.
She led the implementation team behind the creation of the new Home Affairs portfolio and has experience at Defence and Prime Minister and Cabinet, as well as the Bureau of Meteorology.