In a television career that spanned half a century across both sides of the Atlantic, Frost interviewed a long list of the world's most powerful and famous, including virtually every British prime minister and U.S. president of his time. He also was a gifted entertainer, a born TV host, and his amiable and charming personality was often described as the key to his success as interviewer.
"Being interviewed by him was always a pleasure but also you knew that there would be multiple stories the next day arising from it," former British Prime Minister Tony Blair said.
Blair's former communications chief, Alastair Campbell, added on Twitter that Frost was "one of best interviewers because his sheer niceness could lull you into saying things you didn't intend."
Frost, 74, died of a heart attack on Saturday night aboard the Queen Elizabeth cruise ship, where he was due to give a speech, his family said. The BBC said it received the statement from Frost's family saying it was devastated and asking "for privacy at this difficult time." The cruise company Cunard said its vessel left the English port of Southampton on Saturday for a 10-day cruise in the Mediterranean.
Prime Minister David Cameron, one of the first public officials to send condolences, praised Frost for being an "extraordinary man with charm, wit, talent, intelligence and warmth in equal measure," while BBC executives lauded him as "a titan of broadcasting."
Frost began his career almost fresh out of college as the host of an early 1960s BBC satirical news show "That Was The Week That Was," then a pioneering program that ruthlessly lampooned politicians. The show gained a wide following, and Frost's signature greeting, "Hello, good evening and welcome" was often mimicked.
Frost was popular in Britain and just beginning to launch a career on U.S. television when he became internationally known in 1977 with a series of television interviews with Nixon.
They were groundbreaking for Frost and the ex-president, who was trying to salvage his reputation after resigning from the White House in disgrace following the Watergate scandal three years earlier. At the time, it was the most widely watched news interview in the history of TV.
The interviewer and his subject sparred through the first part of the interview, but Frost later said he realized he didn't have what he wanted as it wound down. Nixon had acknowledged mistakes, but Frost pressed him on whether that was enough. Americans, he said, wanted to hear him own up to wrongdoing and acknowledge abuse of power - and "unless you say it, you're going to be haunted for the rest of your life."
"That was totally off-the-cuff," Frost later said. "That was totally ad-lib. In fact, I threw my clipboard down just to indicate that it was not prepared in any way. ... I just knew at that moment that Richard Nixon was more vulnerable than he'd ever be in his life. And I knew I had to get it right."
After more pressing, Nixon relented. "I let the American people down and I have to carry that burden with me for the rest of my life," he said.
The face-off went on to spawn a hit play, and in 2008 a new generation was introduced to Frost's work with the Oscar-nominated movie "Frost/Nixon," starring Michael Sheen as Frost and Frank Langella as Nixon.
Frost was born on April 7, 1939, in Kent, England, the son of a Methodist preacher.
The young Frost began television hosting while still a student at Cambridge University, and soon after graduation he was approached by a BBC producer to front "That Was The Week That Was."
He went on to host a sketch show called "The Frost Report" and became a regular figure on U.S. television. Behind the camera, Frost also co-founded two television companies, London Weekend Television and breakfast station TV-am, churning out a prolific amount of programs.
Over the years his interviewees included a wide-ranging roster of politicians and celebrities, from Russia's Mikhail Gorbachev to Pakistan's Benazir Bhutto to leading entertainment figures such as Orson Welles and the Beatles.
He was the only person to have interviewed the last eight British prime ministers and the seven U.S. presidents in office from 1969 to 2008. Besides the Nixon interviews, one of the more memorable moments included a tense interview with Prime Minister Margaret Thatcher over the sinking of the Argentine warship during the Falklands conflict.
"He could be - and certainly was with me - both a friend and a fearsome interviewer," Cameron said.
In later years Frost kept up his probing questioning of political leaders, although some came to criticize him for being "too nice" to his subjects. Somewhat incongruously, he also hosted a game show called "Through the Keyhole" that spied on the homes of celebrities from 1987 to 2008.
"His sense of humor shone through everything he did," Richard Brock, a producer who worked with Frost at Al-Jazeera, told the broadcaster. "He wasn't all heavyweight, political interviews. He really got a kick out of some of the lighter stuff."
Frost, who wrote about a dozen books, won numerous awards and was knighted in 1993. Most recently he was hosting programs for Al-Jazeera English, where he had worked since its launch several years ago.
He is survived by his wife, Carina, and their three sons.