Roger Ailes: Fox News founder dies at 77
A statement from his wife Elizabeth said she was "profoundly sad and heartbroken", calling him a "patriot".
Mr Ailes ran Fox News for two decades and is credited with transforming it into arguably the most powerful voice in conservative media.
But he stepped down last year after a number of female employees accused him of sexual harassment.
At the time he said he was resigning because he had become a "distraction".
Mrs Ailes' statement said: "During a career that stretched over more than five decades, his work in entertainment, in politics, and in news affected the lives of many millions.
"And so even as we mourn his death, we celebrate his life." The cause of his death is not yet clear.
Before joining Fox, he served as an adviser to several US presidents, from Richard Nixon to George Bush Senior.
Mr Ailes became the founding boss of Fox News in 1996, owned by Rupert Murdoch's 21st Century Fox, turning it into a profits and ratings powerhouse.
It soon became a favourite of right-wing viewers, outpacing liberal-leaning rivals like CNN.
The channel used the slogan "fair and balanced", but its critics saw it as anything but, accusing it of bias and of favouring the Republican Party.
Such was his influence, his biographer Gabriel Sherman quoted him as saying "I want to elect the next president" to a group of Fox executives at a 2010 meeting.
After leaving the company he reportedly helped Donald Trump prepare for the debates during his presidential campaign.