Seven West Media chief executive Tim Worner has resigned with immediate effect after six years in charge.
James Warburton, who had a short-lived spell as chief executive of the Ten Network and quit as APN Outdoor boss last year, has replaced Mr Worner as CEO and managing director.
"All parties agree now is the time for change," chairman Kerry Stokes said in a statement.
"We are fortunate that James was available to commence immediately."
Mr Warburton was chief digital and sales officer at Seven before becoming Ten CEO in 2012.
Mr Stokes had offered him the role of CEO at Seven to prevent his defection but, after a legal hold-up, he switched loyalties only to have his contract terminated 13 months later with the network haemorrhaging viewers and money.
Mr Worner had been with Seven for 25 years and led Seven West Media for six, a period that included a legal battle that followed the 2016 revelation of a two-year affair with a junior employee.
He helped engineer last year's high-profile grab of cricket from the Nine Network, with Seven paying $450 million over six years to broadcast all home Test matches and 43 Big Bash League games.
"It's with mixed emotion that I tender my resignation, however Seven – a company I love – is a very different company now from the one I joined 25 years ago," Mr Worner said.
"It's changed faster than ever in these last few years and that's down to the hard work of the best team in the business."
Do you have a story tip? Email: firstname.lastname@example.org.