Tom Brokaw, 80, is retiring from NBC News after 55 years.

Brokaw began at NBC in its Los Angeles bureau in the 1960s, where he covered Ronald Reagan's first run for public office and the assassination of Robert F. Kennedy.

Brokaw was a White House correspondent during Richard Nixon's presidency, and began co-hosting the "Today" show in 1976. He started hosting "Nightly News" in 1983.

For two decades, Brokaw, ABC's Peter Jennings and CBS' Dan Rather were the nation's most visible TV broadcasters.

He was NBC’s lead anchor on its “Nightly News” for more than 20 years before Brian Williams succeeded him in 2004.

He is author of “The Greatest Generation,” about those who brought America through World War II.

Williams said he will continue his writings with books and articles.