Longtime American political columnist Robert Novak has died at 78 after battling brain cancer.

The Chicago Sun-Times said Novak's wife, Geraldine, confirmed the journalist passed away at his home in Washington, D.C., Tuesday.

"He was someone who loved being a journalist, loved journalism and loved his country and loved his family," Geraldine told the newspaper.

Novak, a Conservative columnist for the Sun-Times since 1966, was co-host of CNN's Crossfire from 1980 to 2005, when he left to join Fox News.

In recent years, he became a newsmaker himself. In 2003, he was the first to publish the name of Valerie Plame as a CIA operative.

That column came just eight days after Plame's husband, U.S. diplomat Joseph Wilson, said the Bush administration had distorted prewar intelligence to amplify the Iraqi threat.

Novak has said he has been criticized many times over since that column and lost his standing among many in journalism.

He was diagnosed with a brain tumour in July 2008, just a week after he hit a homeless man with his car in downtown Washington and tried to drive away. He was stopped by someone and has said that he never realized what had happened.

Days later, he lost his way driving to his dentist's office. That triggered a medical examination that uncovered the tumour. His doctor told him he had six months to a year to live.

In a column, Novak expressed wonder about the well-wishers that emerged after he revealed his condition.

"I thought that 51 years of rough and tumble journalism had made me more enemies than friends, but my recent experience suggests the opposite may be the case," he wrote in 2008.

Novak had been retired for a year already at the time of his death.

In a tribute to her friend, Newsweek columnist Eleanor Clift, a self-described liberal, called Novak a "scruffy, shoe-leather reporter" who became a political insider and a must-read in Washington's political circles.