King's doctor told him the cancer was malignant, but because they caught it in stage 1 they were able to surgically remove the tumour.
He underwent surgery to remove 20 per cent of his lung on July 17 at Cedars-Sinai Medical Center in Los Angeles and was back to work in two weeks.
If the doctors hadn't spotted the tumor in the chest scan they told him he would have 'had trouble' a few years down the road.
That's because often lung cancer doesn't show symptoms until later stages.
If the disease is caught in a late stage and has grown to a significant size or has spread, it can be inoperable and cause death.
Since the surgery he's been back to the hospital for follow-up visits, and said that everything is looking normal and healthy.
"They showed me my last chest X-ray, which is all clear," he told Us. "It was fun to see where that spot was and there is no spot now."
The broadcast journalist has had a myriad of health issues through the years, including diabetes, heart disease and prostate cancer. However, those prior health issues proved beneficial in catching his lung cancer early, he said, because he goes in frequently for screenings.
In February of 1987 he had his last cigarette after suffering a heart attack, for which he underwent a bypass procedure.
Doctors were able to catch his prostate cancer early, too, and were able to treat it entirely with radiation.
King told Us that the recent lung cancer diagnosis is related to his prior tobacco use, even though he hasn't had a cigarette in 30 years.
"I smoked for 30 years, the day of the day of the heart attack," he said during an interview with Extra.
"The last day of the heart attack, I never smoked again, and I smoked three packs a day - I smoked in the shower.
"Thirty years later, I said to the doctor [about the lung cancer diagnosis] 'Is this connected with that?' Absolutely."
And now, he said he hopes others can learn from his diagnosis.
"When you are [getting a checkup, get a chest X-ray because lung cancer ain't going to tell you it's there, but a simple chest X-ray will," he said.
"If it shows you one little spot, you will do a CAT scan. They are painless."
And King isn't the only celebrity urging people to get scanned for the disease.
The Rolling Stones' guitarist Ronnie Wood was diagnosed with lung cancer in May after a tumor was discovered by chance that proved to be cancerous.
The 70-year-old smoked for roughly 50 years before quitting last year when his twin daughters, Gracie and Alice, were born.
Wood was diagnosed when his doctors asked if he wanted to have a chest scan, and said the news didn't surprise him, but that he was glad he'd done it so they could just "get it out" of him.
Now, he advocates for people who reach a certain age to undergo chest scans, especially if they have a history of smoking.
And for now, King he doesn't plan on slowing down.
"I will probably die on the air," he said, explaining that even after the intrusive surgery he's never felt better.
"I have beaten so many things health-wise to feel this good now. I have no plans to retire."
Though King is an avid Twitter user, he hasn't mentioned the cancer on his social media yet.
Throughout his career King has worked as an American television and radio host and been recognized with a variety of awards, including 10 Cable ACE Awards.
He first gained notoriety in 1978 when he started working as an all-night national radio broadcaster.
Then, in 1985 he started hosting the nightly programme Larry King Live on CNN.
Currently he hosts Larry King Now on Hulu and RT America during the week.
And during his long career, King has been married eight times to seven different women, one of who he married twice. His current wife is Shawn Southwick, a 57-year-old singer, actress and television host.
He has five children, nine grandchildren and four great-grandchildren.
