NBC's Tim Russert speaks at the 60th anniversary celebration of NBC's Meet the Press at the Newseum in Washington in this Nov. 14, 2007, file photo . Renowned journalist Russert, 58, collapsed and died while at work Friday at the NBC Washington bureau.

Washington ? Tim Russert, a political lifer who made a TV career of his passion with unrelenting questioning of the powerful and influential, died of a heart attack Friday in the midst of a presidential campaign he’d covered with trademark intensity. Praise poured in from the biggest names in politics, some recalling their own meltdown moments on his hot seat.

Russert, 58, was a political operative before he was a journalist. He joined NBC a quarter century ago and ended up as the longest-tenured host of the Sunday talk show “Meet the Press.”

He was an election-night fixture, with his whiteboard and scribbled figures, and was moderator for numerous political debates. He wrote two best-selling books, including the much-loved “Big Russ and Me” about his relationship with his father.

He was NBC’s Washington bureau chief.

President Bush, informed of Russert’s death while at dinner in Paris, saluted him as “a tough and hardworking newsman. He was always well-informed and thorough in his interviews. And he was as gregarious off the set as he was prepared on it.”

NBC interrupted its regular programming with news of Russert’s death and continued for several hours of coverage without commercial break. The network announced that Tom Brokaw would anchor a special edition of “Meet the Press” on Sunday, dedicated to Russert.

Competitors and friends jumped in with superlative praise and sad recognition of the loss of a key voice during a historic presidential election year. Known as a family man as well, he had been named Father of the Year by parenting organizations.

Familiar NBC faces such as Brokaw, Andrea Mitchell and Brian Williams took turns mourning his loss.

Williams called him “aggressively unfancy.”

“Our hearts are broken,” said Mitchell, who appeared emotional at times as she recalled her longtime colleague.

Bob Schieffer, Russert’s competitor on CBS’ “Face the Nation,” said the two men delighted in scooping each other.

“When you slipped one past ol’ Russert,” he said, “you felt as though you had hit a home run off the best pitcher in the league. I just loved Tim and I will miss him more than I can say.”