At a press conference on Thursday morning, it was his duty to announce the arrests of 15 people following the largest counter-terrorism raid in Australian history. They were suspected not only of terrorism-related activity, he said, but of planning to carry out attacks on members of the public. More than 800 federal and state police officers were involved in the operation.

So who is the man leading the charge?

Widely respected, Mr Colvin has been acting commissioner of the AFP since September 7. He is a Harvard-educated career cop who joined the force in 1990, where his early work focused on investigating narcotics, money laundering, politically-motivated crime and terrorism financing. He was the national co-ordinator for counter-terrorism during the 2002 Bali bombings, for which he was named a Member of the Order of Australia.

Later, he worked in the area of high-tech crime and managed Operation Centurion, Australia's largest investigation into online child pornography. He was chief of staff to former commissioner Mick Keelty and was awarded the Australian Police Medal in 2008. In June this year, he moved back into the national security portfolio and has since spoken publicly in support of controversial internet data retention plans. He also briefed media on the AFP's deployment to the MH17 crash site.

Former AFP agent Alastair MacGibbon, who has had a professional relationship with Mr Colvin for 25 years, said "AJ" - as he is commonly known - was an energetic straight-shooter with significant experience in sensitive counter-terrorism operations.

"He's no babe in the woods when it comes to understanding how Canberra operates," he said.

"He has a history working in complex, high-pressure, political investigations. He's not a shoot-from-the-hip kind of guy. He's considered, he has a strong internal compass, yet he understands how to handle internal operations.

"It's a safe pair of hands to be in charge."

Mr Colvin, who is married with two children, could hardly have met with a more eventful start in office. Last Thursday the AFP was forced to apologise when it accidentally left a plastic explosive device at Sydney Airport following a training exercise. Then on Friday, he flanked Prime Minister Tony Abbott and ASIO head David Irvine to announce the country's official terror alert level had risen from "medium" to "high".

He assumed his position after former commissioner Tony Negus stepped down, declining to serve a second term. Mr Negus came under fire earlier this year when it was alleged his son Mitchell had been given special treatment when he was allowed to graduate from the AFP while injured.