It is easy to forget, amid the jokes about the suspenders, the many wives, and his advancing age, that for quite a while, CNN star Larry King was the most popular man on cable television.

This was mostly in the '90s, when King turned an eccentric, radio-born interview show into a venue for the biggest celebrities to hang loose, and for political heavyweights to speak, almost unfiltered, to a nationwide audience.

It is where H. Ross Perot signaled his run for president, where O.J. Simpson's slow-speed car chase revealed the ratings gold behind his real-life soap opera, and where politicians like Bill Clinton turned when more conventional TV outlets proved too challenging.

When he was most popular, King balanced one of cable TV's most-watched shows with one of radio's most-listened-to programs, a column in USA Today, a syndicated TV show, various TV specials, and a cameo appearance in any movie or television show that needed a deep-voiced guy in front of a microphone.

"He was the first major star of cable . . . not just cable news," said Jonathan Klein, King's boss until being forced out in September as CNN's U.S. president. "He helped to get millions of Americans into the habit of going beyond Channel 11. At his height, the whole country was talking about Larry King."

As King completes his last broadcast of Larry King Live on Thursday, capping a quarter-century at CNN and five decades of broadcasting, critics may focus on the 77-year-old's ratings declines and a departure that seems as much CNN's idea as his own.

But when the most popular person in cable news is Fox News Channel's partisan bully Bill O'Reilly, it's worth asking: Did King leave cable news, or did the audience, thirsty for partisan combat and opinion, leave him?

"There was a time when Larry King was perfect for television, when CNN was the only place you could go for cable news," said media analyst Andrew Tyndall. "Fox and MSNBC changed the definition of cable news in prime time from news to politics. And now, I don't think, in modern-day cable news, the softer, nonpolitical format works anymore."

King's longtime senior executive producer Wendy Walker, who has shepherded Larry King Live for 17 of the show's 25 years, will cite almost any other cause - the explosion of alternate news sources on TV and online, the proliferation of ways for celebrities to speak to the world - rather than speculate on how rivals' partisan punditry may have affected her boss' ratings.

Hosts like O'Reilly may pick public fights to spread their own fame, the producer said, but she never felt comfortable making King the center of any story.

In truth, King's style has always been a mash-up of the best and worst of television interviewing. He's an engaging personality who listens to guests and gets some of the most famous names on the planet to relax in a comfortable space.

But he's also a relentless schmoozer whose legendary insistence on not preparing for interviews leaves him vulnerable. Back before sitting presidents would appear on shows like MythBusters or The View, critics groused that King gave politicians and big celebrities a TV platform to spin their problems, buoyed by softball questions.

Larry King's eccentric, spectacular media odyssey began in Florida.

That's where Larry Zeiger, a kid from Brooklyn with less than $20 to his name, landed in 1957, snagging a job first at WAHR radio in Miami Beach and later WIOD, hosting a show from a houseboat docked across Collins Avenue from the Fontainebleau hotel. The on-air name King was picked minutes before his radio debut.

Here King developed the style that would make him famous, snagging celebrities like Bobby Darin and Paul Newman with no chance to prepare. It's also where he built his first media empire, with jobs as a color commentator for the Miami Dolphins, writing a column for newspapers such as the Miami News and Miami Herald, and TV jobs at WTVJ and WPLG.

King also had problems; most famous was a 1971 arrest for grand larceny when a friend claimed he stole $5,000 after amassing more than $350,000 in debt. In a flash, the radio program, TV shows, and newspaper columns were gone. He eventually landed as an announcer at a horse-racing track in Shreveport, La.

Then, a new general manager at WIOD noticed listener surveys where fans kept asking about this guy named Larry King. So he rehired him.

In 1978, the Mutual Broadcasting Network asked King to host a syndicated radio show, eventually moving him to Washington. Then CNN founder Ted Turner persuaded King to try a TV version of the radio show.

Walker and CNN haven't confirmed who will guest on King's final show; rumors say his first-ever guest, former New York Gov. Mario Cuomo, may top a show broadcast from New York, Washington, and the program's current home base, Los Angeles.

Though King initially said that leaving was his idea, he has since told New York magazine he quit after CNN offered just a one-year contract extension, which executives have never confirmed. He is still expected to appear in four CNN specials a year.

His ratings have sunk substantially, down from an average of 1.8 million people in November 2000 to 637,000 viewers last month, according to the Nielsen Co., coinciding with CNN's drop to third in prime-time ratings. So it is small surprise that King and CNN would part ways now, making room for the brasher style of British chat-show host, journalist, and reality-TV judge Piers Morgan.

Andrew Heyward, a former head of CBS News who now works as a consultant on digital-media issues, suggested that King was leaving cable news as it becomes the ultimate expression of what he started.

"Larry paved the way for a more personality-driven cable-news program," Heyward said. "Now, it's evolved beyond reassuring personalities, to personalities with sharp opinions. You could argue that rather than cable leaving Larry King behind, maybe it's just caught up to him."