Radio talkback host David Oldfield has left 2UE for "family reasons".
The founder of the One Nation political party said in a statement it was "a very difficult decision" not to return to his nightly 8pm to midnight shift.
“It would not have been in the best interests of my wife and children,” he said.
“My first priority must be to my family responsibilities, and in particular, to my two very young sons. This means I will not be returning to nights in 2013."
Mr Oldfield, a former Tony Abbott staffer, came to fame in the late 1990s as the driving force behind controversial independent MP Pauline Hanson - the only federally elected One Nation member.
The controversial right-wing commentator replaced Steve Liebmann as host of the morning program on 2UE in December 2010, before moving to the nightly slot in April 2012.
Chris Parker, 2UE's general manager, congratulated Mr Oldfield on his ratings.
“David provided a platform for vigorous debate every night and for that he is to be commended.
“Some might not have always agreed with David Oldfield's opinion, but at least everyone always knew where they stood with him," he said.
Mr Parker said an announcement will be made next week as to who will replace Mr Oldfield's shift.