- Radio roots -
Tributes from the media, politicians and Hollywood stars poured in, led by Putin, who hailed the interviewer's "great professionalism and unquestioned journalistic authority," according to the Kremlin.
Veteran CNN foreign correspondent Christiane Amanpour remembered King as "a giant of broadcasting and a master of the TV celebrity/statesman-woman interview."
She added: "His name is synonymous with CNN and he was vital to the network's ascent. EVERYONE wanted to be on Larry King Live. May he Rest in Peace."
Star Trek icon and social media personality George Takei noted how King understood "human triumph and frailty equally well," while Kirstie Alley, of "Cheers" fame, described him as "one of the only talk show hosts who let you talk."
Born Lawrence Harvey Zeiger on 19 November, 1933, to poor Russian Jewish immigrants in working-class Brooklyn, New York, King says he never wanted to be anything but a radio broadcaster.
At the age of 23 he went to Florida to try and find a job.
He became a disc-jockey for a Miami radio station in 1957, changing his name to King when the radio's manager told him it was "too ethnic".
For another Miami Beach radio station he recorded programs in a restaurant, doing live audience interviews.
In 1978 he went to Washington where he anchored a national late-night radio call-in show, before being spotted by CNN, a channel founded in 1980, which hired him for its nighttime programs in 1985.
- One million viewers -
"Larry King Live", which ran from 1985-2010, broadcast six nights a week to more than 200 countries. CNN puts his total number of interviews at 30,000.
At the height of its success the show attracted more than a million viewers every night, making King the star of cable television, on the back of which he negotiated an annual salary of more than $7 million.
Structured in two parts, the show opened with King, typically in his signature rolled-up shirtsleeves and multi-colored ties, interviewing his guests in his relaxed style.
The second part of the show had the guest answering questions phoned in by viewers from around the world.
"I don't have an agenda. I don't assume the answer," King told the Miami Herald in 2017 of his approach to the job. "I never learned anything when I was talking. Listening is as important," he said.
While critics found his easy-going interviewing style too soft, others saw it as the key to King's appeal, drawing so many star guests to his show and helping CNN establish itself with the scoops he won.
"I'm not interested in embarrassing (guests) nor am I interested in sucking up to them," he told AFP in 1995. "I'm just curious."
- The show goes on -
After CNN King continued to do interviews on his own website and then, in 2013, he hosted a new show, "Larry King Now", on Russia Today, a government-funded Russian international television network.
His private life has been colorful too: after 22 years of marriage he divorced his seventh wife Shawn Southwick in 2019, having filed eight times for a divorce -- he married one wife twice.
"Instead of goodbye, how about so long?" he said, voice breaking, as he signed off from his show that made him famous.