A household face as co-host of CNN's "Crossfire," Novak had been a columnist for the Chicago Sun-Times for decades. The brain tumor diagnosis came less than a week after he struck a homeless pedestrian in downtown Washington with his Corvette and drove away.
"He was a Washington institution who could turn an idea into the most discussed story around kitchen tables, congressional offices, the White House, and everywhere in between," Senate Republican Leader Mitch McConnell of Kentucky said in a statement.
Said House Republican Leader John Boehner of Ohio: "Bob made remarkable contributions in the field of journalism and to the American political landscape."
In recent years, Novak ended up actually being a part of a big Washington story, in ways he likely never intended, becoming a central figure in the Valerie Plame CIA leak case.
Novak was the first to publish the name of the CIA employee, and he came under withering criticism and abuse from many for that column, which Novak said began "a long and difficult episode" in his career.
"I had a terrific time fulfilling all my youthful dreams and at the same time making life miserable for hypocritical, posturing politicians and, I hope, performing a service for my country," Novak wrote in his memoir, "The Prince of Darkness: 50 Years reporting in Washington."
Actually Novak had been dubbed the "prince of darkness" by a journalist friend early in his career, and he embraced it. He wrote in that 2007 memoir that he became proud of the label derived from his "unsmiling pessimism about the prospects for America and Western civilization."
"He loved being a journalist, he loved journalism, he loved his country and his family," Geraldine Novak told The AP.
Novak, editor of the Evans-Novak Political Report, had been a columnist for the Chicago Sun-Times for decades. He is perhaps best known as a co-host of several of CNN's political talk shows, where he often jousted with liberal guests from 1980 to 2005. One of the best-known was "Crossfire."
While he became known as a conservative for his role on "Crossfire" and other CNN political shows like "The Capital Gang," he differed with conservatives on many issues, expressing doubts about invading Afghanistan and frequently criticizing the war in Iraq.
Novak wrote in his book about often giving politicians the choice of being a source or a target, a strategy that often produced scoops for his column.
With a lengthy list of highly placed sources, a high public profile and a relentless approach to reporting his column, Novak produced many scoops.
Among those scoops included a 2003 column in which he outed Plame as a CIA agent. The article was published eight days after Plame's husband, Joseph Wilson, said the Bush administration had twisted prewar intelligence to exaggerate the Iraqi threat of nuclear weapons.
Citing two Bush administration officials, Novak revealed Plame worked for the CIA on weapons of mass destruction. That blew her cover as a CIA operative and led to the investigation of who leaked that information, and eventually to the conviction of I. Lewis "Scooter" Libby, Vice President Dick Cheney's former chief of staff. Libby's prison sentence was later commuted by President Bush.
Born and raised in Joliet, Ill., Novak began his career in journalism in high school as a sports stringer for the Joliet Herald-News, then worked at the Champaign-Urbana Courier while attending the University of Illinois.
Following college, he served stateside in the U.S. Army as a lieutenant during the Korean War from 1952-54. He went on to work for The Associated Press in Omaha, Neb., and in Indianapolis, eventually working for the AP's Washington bureau, where he covered congressional delegations for several Midwestern states.
In 1958, Novak joined the staff of the Wall Street Journal and soon became their chief congressional correspondent.
In 1963 he teamed up with the late Rowland Evans Jr. to pen a political column, "Inside Washington," that lasted 30 years. They were journalism's odd couple -- Evans was polished and charming while Novak was often rumpled and grouchy.
Evans died in March 2001, and Novak continued to write the column until his brain tumor diagnosis in July.
From 1980 to 2005, Novak worked as a commentator for various political talk shows on CNN, with "Crossfire" one of the best known. His last CNN appearance in August 2005 was a memorable one: After swearing on the air, he walked off the set during a political debate with Democratic strategist James Carville. Novak quickly apologized, but CNN never let him back on the air.
Jim Walton, president of CNN Worldwide, said in a statement: "Bob shared generously with CNN and with CNN viewers his authority, credibility, humor and towering presence. We are grateful to have worked alongside him."
Following his departure from CNN, Novak was an occasional contributor to Fox News.
"Whether it was for the AP, Wall Street Journal, Chicago Sun-Times or on Crossfire, Robert Novak was a strong voice for journalism and the American people. 'Inside Washington'... consistently brought the reality of Washington, from one end to the other, to life," said House Republican Whip Eric Cantor, R-Va., in a statement.
American Conservative Union Chairman David Keene called Novak "a true giant...a courageous journalist, a man of ideas (who) spent a lifetime fighting for what he believed to be right."
"The combative Bob Novak, beloved by so many who knew him only through his television persona, was only a part of the personality of one of the most patriotic, compassionate and loyal men I have ever known."
In addition to his memoir, Novak wrote books about the Republican Party and former President Lyndon Johnson.
Days before his tumor was discovered in mid-July 2008, Novak was given a $50 citation after he struck a homeless man with his black Corvette in downtown Washington. He kept driving until he was stopped by a bicyclist, who said the man was splayed on Novak's windshield.
Days later, Novak fell ill on Massachusetts' Cape Cod while visiting his daughter, Zelda, and was rushed to the hospital, where the diagnosis was made. It was Novak's third cancer diagnosis. He underwent surgery in 2003 to remove a cancerous growth on his kidney.
Novak had been diagnosed with cancer at least three times previously. He underwent surgery in 2003 to remove a cancerous growth on his kidney and was under medical observation for a possible recurrence.
A son of Jewish parents, he converted to Catholicism at age 67 after attending Catholic services for several years.
Novak is survived by his wife Geraldine, who was a secretary for President Johnson, their daughter and a son, Alex.