Former NBC News anchor Tom Brokaw announced Russert's death, calling Russert "our beloved colleague and one of the premier journalists of our time.
"This news division will not be the same without his strong clear voice. He'll be missed, as he was he loved, greatly," said Brokaw.
Russert famously boiled down the hotly contested 2000 presidential election when on election night he scribbled the words "Florida, Florida, Florida" on a white board, succinctly explaining where the election would ultimately be decided.
TV Guide named that moment one of the "100 Most Memorable TV Moments" and the Washington Post has credited Russert with coining the phrase "red state" and "blue state" to describe those states that typically vote Republican or Democratic.
Russert's colleagues at NBC expressed shock and sadness at their colleagues untimely death.
"We are heartbroken at the sudden passing of Tim Russert. We have lost a beloved member of our NBC Universal family, and the news world has lost one of its finest. The enormity of this loss cannot be overstated. More than a journalist, Tim was a remarkable family man. Our thoughts and prayers are with his wife, Maureen, their son, Luke, and Tim's entire extended family," said Jeff Zucker, president and chief executive officer of NBC Universal.
Steve Capus, president of NBC News, called Russert's death "a loss for the entire nation.
"Everyone at NBC News is in shock and absolutely devastated. He was our respected colleague, mentor and dear friend. Words can not express our heartbreak. Our thoughts and prayers are with Maureen, Luke, Big Russ and all of Tim's family," Capus said in a statement.
Many of those politicians who found themselves on the sharp end of Russert's questions also took time Friday to praise him.
"As the longest-serving host of the longest-running program in the history of television, he was an institution in both news and politics for more than two decades. Tim was 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," President Bush said in statement.
Presidential contenders Sens. Barack Obama and John McCain, each of whom spent more than one occasion on the other side of the "Meet the Press" table, expressed their sympathies.
Both candidates called Russert "a friend."
"There wasn't a better interviewer in TV, not a more thoughtful analyst of our politics, and he was also one of the finest men I knew. Somebody who cared about America, cared about the issues, cared about family. I am grief stricken with the loss and my thoughts and prayers go out to his family," said Obama.
McCain echoed many of those same sentiments: "I am very saddened by Tim Russert's sudden death. Cindy and I extend our thoughts and prayers to the Russert family as they cope with this shocking loss and remember the life and legacy of a loving father, husband and the pre-eminent political journalist of his generation. He was truly a great American who loved his family, his friends, his Buffalo Bills and everything about politics and America. He was just a terrific guy."
George Stephanopoulos, host of ABC News' "This Week" and Russert's Sunday morning competition, said Russert "loved everything about politics and journalism -- because he believed in it.