Rachel Noble, the deputy secretary executive in the department, and a former staffer of the Australian Signals Directorate, will return to take up the post.
Announcing Noble's appointment on Wednesday, ASD director-general Mike Burgess said in a statement: "I’m delighted that Rachel’s agreed to return to ASD to take this important and challenging role. The cyber threat is real and Rachel is ideally qualified to confront it.”
Noble said: “I am really looking forward to returning to ASD to work with Mike and his team.
Noble has previously held leadership positions in Home Affairs, Defence (including ASD) and the Department of Prime Minister and Cabinet.
As PM&C’s National Security chief information officer and cyber policy co-ordinator, she co-ordinated whole of government policy on cyber issues and improved information sharing among the national security community. Noble received a Public Service Medal for this work.
“Rachel Noble possesses a formidable skillset and the new role brings together her experience in cyber, science and security,” Burgess said, “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.”
Noble worked for Optus before joining the public sector. She holds a Masters of Business Administration in Technology Management and a Bachelor of Science with Honours.
MacGibbon was said to have quit in order to capitalise on the growing market for cyber security specialists in the private sector.
There was also a view expressed in some circles that MacGibbon had left because he would be uncomfortable working with Labor's Ed Husic, who would have been handling the digital affairs portfolio had the party won the election as expected.
Husic had been critical of the way that some foreign companies like Microsoft had been granted Protected cloud status for storing top-secret government data, something which MacGibbon fiercely defended.
Commenting on Noble's appointment, Sam Ghebranious, senior director, Australia and New Zealand at American security firm Forcepoint, said: "“Rachel’s appointment to lead the ACSC is a hugely welcome step and reflects our government’s resolve to tackle the cyber threat head-on.
"The rise in number of cyber attacks on Australia’s globally renowned institutions is alarming and now is the time for government agencies and enterprise sector to come together to put up robust defences.
"Rachel’s strong experience in cyber and national security reflect the current government’s intention to lead the country in this digitally transformed economy.”