WASHINGTON (CNN) -- The moderator's chair on NBC's "Meet the Press" stood empty on Sunday in remembrance of Tim Russert, the man who had occupied it for 17 years.

The moderator's chair on NBC's "Meet the Press" stood empty Sunday in remembrance of Tim Russert. more photos »

As the show's host, Russert became a mainstay of television journalism's political talk.

He died Friday of apparent heart attack, according to the network. He was 58. The network said Russert collapsed while at work.

Colleague and former NBC anchor Tom Brokaw, who broke the news about the anchor's death, spoke on Sunday the familiar first four words of the news program, "Our issues this Sunday." He noted that those were the same words Russert had been recording for the show when he collapsed and died.

"Our issue this sad Sunday morning is remembering and honoring our colleague and friend," Brokaw said.

"He said he was only the temporary custodian," of this program, which he called a national treasure, Brokaw said. "Of course, he was so much more than all that."

Brokaw sat among some of Russert's other colleagues in the front of the show's set, including Pulitzer Prize-winning author Doris Kearns Goodwin and political analysts Mary Matalin and James Carville, who is also a CNN contributor.

"This is where you separated the men from the boys," said Matalin, who is married to Carville. "You weren't a candidate until you came on this show."

A montage of clips from past years showed various politicians -- former President Bill Clinton, President Bush, former presidential candidate Ross Perot, Homeland Security Secretary Michael Chertoff -- sitting across the table from Russert. Watch politicians, journalists pay homage to Russert »

Some showed the politicians as they squirmed.

"Look, I was asked -- I shouldn't have said that," New Mexico Gov. Bill Richardson said on the show in May 2007.

Richardson had appeared on the show as part of the "Meet the Candidates 2008" series, and was grilled by Russert about his contradictory positions on numerous issues.

"So you're - I've been in public life for 25 years, you're going to find a lot of these; it seems you found them all here," he said, smiling somewhat sheepishly.

"I'm just trying to set the record and trying to give you a chance to respond, which is fair," Russert had responded.

In another clip at the end of an April 2006 show, Sen. John McCain told Russert, "I haven't had so much fun since my last interrogation."

Russert had appeared as an unlikely icon for television news, with his cherubic face and dimpled chin, but he was a prolific interviewer and tireless journalist, one with an intimidating breadth of political knowledge and insight.

"It was a very easy show to prepare for in the sense that you knew he was not going to ask you any questions out of left field; you knew his thing was going to be entitlements, you knew his thing was going to be past statements, you knew where he was coming from," Carville said Sunday of "Meet the Press."

Matalin countered: "It was simple in the fact that there was no 'gotcha,' but it was not easy. Because you had to be 10 questions deep, because he was going to be 12 questions deep."

As news of his death hit the airwaves and Internet, tributes rolled in -- with nearly everyone praising his prowess as a journalist and as an interviewer.

Bush, in a written statement, called Russert "a tough and hardworking newsman."

"He was always well-informed and thorough in his interviews," Bush said. "And he was as gregarious off the set as he was prepared on it."

Longtime CBS news anchor Walter Cronkite said, "Broadcast journalism lost one of its greats today. Tim Russert was a giant in our field -- a standard-bearer of journalistic integrity and ethics. His masterful interviews and roundtable discussions are legendary. This is a tragic loss for journalism and for all who were privileged to know him."

But colleagues who knew him best also praised his warmth, and described him as a mentor.

"I think it's so poignant that we're talking about Tim on Father's Day because he was a father to so many of us," said California first lady Maria Shriver, who once worked for NBC.

On Friday, NBC chief foreign affairs correspondent Andrea Mitchell said, "He was always teaching each of us to be as rigorous as he was in looking at all the facts, examining everything and then being as balanced and fair and down-the-middle as anyone could possibly be."

Washingtonian Magazine once dubbed Russert the best and most influential journalist in Washington, D.C., describing "Meet the Press" as "the most interesting and important hour on television."

In 2008, Time Magazine named him one of the 100 most influential people in the world. His two books -- 2004's "Big Russ and Me" and 2006's "Wisdom of Our Fathers" -- were both New York Times bestsellers.