King first broke the news himself via his Twitter account.
Here's what he said at the start of Tuesday night's show:
Before I start the show tonight, I want to share some personal news with you. 25 years ago, I sat across this table from New York Governor Mario Cuomo for the first broadcast of "Larry King Live."
Now, decades later, I talked to the guys here at CNN and I told them I would like to end "Larry King Live," the nightly show, this fall and CNN has graciously accepted, giving me more time for my wife and I to get to the kids’ little league games.
I’ll still be a part of the CNN family, hosting several Larry King specials on major national and international subjects.
I’m incredibly proud that we recently made the Guinness Book of World Records for having the longest running show with the same host in the same time slot. With this chapter closing I’m looking forward to the future and what my next chapter will bring, but for now it’s time to hang up my nightly suspenders.
Here's how King first broke the news -- via Twitter, of all things:
King's exit will now step up the speculation over who might replace him. Top contenders have included "America's Got Talent" judge Piers Morgan, who's been rumored for weeks to be in line for the gig.
Another name frequently mentioned is Ryan Seacrest, who has served as a substitute on the show -- and whose radio contract with Clear Channel is up. Seacrest is rumored to be considering giving up his morning show, which would leave more time for a CNN show.
Another possibility, Katie Couric, is seen as a longshot. Couric is expected to remain as anchor of the "CBS Evening News."
In regards to the speculation over King's replacement, CNN said in a statement: "Today is about Larry. We will announce plans for the 9pm hour in the weeks ahead."
Here's CNN's official statement about King:
Just as CNN redefined the news business, Larry King defined the art of the television interview. His candor, curiosity and compassion are legendary, and his ability to interview people from all walks of life—world leaders, celebrities and everyday people—has made him an icon.
Having conducted nearly 50,000 interviews over 50-plus years in broadcasting, Larry deserves to take some time for himself and his family. After 25 years at CNN, he will conclude Larry King Live on his own terms, sometime this fall. We are proud and grateful that Larry will continue the next chapter of his storied career at CNN and will host several specials over the coming years.
In a note to staffers, CNN U.S. topper Jon Klein called King "a giant in the industry for as long as most of us can remember":
TO: CNN Colleagues
FR: Jon Klein
Larry King has asked that I share with you a message to his audience that will be broadcast tonight at the top of his show. After 25 years, Larry has decided to take a step back from the nightly grind. He wants to take some time for himself and his family. So he will end his run with Larry King Live on his own terms, sometime this fall.
He is not leaving CNN. Larry is a beloved member of the CNN family and he will continue to contribute to our air with periodic specials.
Larry has been a giant in the industry for as long as most of us can remember. Anyone who ever mattered has sat for an interview on Larry's iconic set. They all know the man it is our privilege to call our colleague and friend--tireless and curious, respectful and inquisitive, caring, generous, influential, a citizen of the world.
We will celebrate his tenure in proper fashion over the coming months. Today is about Larry and about the beginning of a new chapter. It is not about good-bye.
Here's Larry King interviewing Lady Gaga on a recent episode: