Williams was born in Colon, Panama, near the Canal Zone. His father, Roger, was a boxing trainer and his mother, Alma, a seamstress. He was raised in the Episcopal Church. When he was four years old his family...including older siblings Elena and Rogelio...moved to the Bedford-Stuyvesant neighborhood in Brooklyn, New York. He then won a scholarship to attend Oakwood School in Poughkeepsie, New York. He became president of the student body, editor of the student paper and was captain of the baseball, cross-country and championship basketball team. He then won a scholarship to Haverford College where he graduated with a B.A. in philosophy in 1976.

During college, Williams worked for three years as a reporter intern for the Philadelphia Bulletin. He also won a Dow-Jones Newspaper Fund Award for outstanding young journalists and worked for a summer as an editor at the Providence Journal before returning to finish college. After graduation, he won an internship at The Washington Post. He worked at the paper from 1976 to 2000. During his tenure at the Post, he held several positions, including metropolitan staff writer. While on the local staff he wrote a prize winning 6 part series on the problems in the DC public schools that was nominated for a Pulitzer Prize. His investigative reporting on corruption in Mayor Marion Barry’s administration also won several awards. He later served on the Post’s national staff — covering every major political campaign from 1980 to 2000 — and as a political analyst. He also wrote as the paper’s White House correspondent, as an editorial writer, op-ed columnist and for the Post Sunday Magazine.

While at the Post he became a regular panelist on Inside Washington, a leading weekly Washington political affairs program. In 1990 CNN signed him to be a host for its highly rated Crossfire program with co-hosts Bob Novak, Michael Kinsley and Pat Buchanan. He also regularly appeared on Capitol Gang and hosted Crossfire Sunday with Lynne Cheney.

In 1996, Williams became host of the syndicated television program, America’s Black Forum. The show’s regular panelists included Julian Bond, Niger Innis, Deborah Mathis and Armstrong Williams.

Williams joined the Fox News Channel as a political contributor in 1997. He is a regular panelist on Special Report with Bret Baier and Fox News Sunday With Chris Wallace. He also regularly appears on The O'Reilly Factor and has served as a guest host on the top rated cable news show.

Due to Williams' commentary on the Fox News Channel, NPR requested that the FNC stop identifying him as an NPR host. NPR Ombudsman Alicia Shepard maintained that: "Williams tends to speak one way on NPR and another on Fox." Williams' following comment triggered the move:

Michelle Obama, you know, she's got this Stokely Carmichael in a designer dress thing going. If she starts talking, as Mary Katharine [Ham, a conservative blogger] is suggesting, her instinct is to start with this blame America, you know, I'm the victim. If that stuff starts coming out, people will go bananas and she'll go from being the new Jackie O to being something of an albatross.

"As a result of this latest flap, NPR's Vice President of News, Ellen Weiss, has asked Williams to ask that Fox remove his NPR identification whenever he is on O'Reilly."

Williams joined NPR in 1999 as host of the daily afternoon talk show Talk of the Nation. During his nearly two years as host the show gained its highest ratings. He then served as senior national correspondent for NPR, interviewing newsmakers as well as providing analysis of major events in interviews with the anchors for the newsmagazines Morning Edition, All Things Considered and Weekend Edition Saturday and Sunday.

Williams is the recipient of an Emmy Award for his work in television documentary writing, and has earned widespread critical praise for a series of documentaries including Politics: The New Black Power, A. Philip Randolph: For Jobs and Freedom, Civil Rights and The Press, Riot to Recovery and Dying for Healthcare.

He was the scriptwriter for Oprah Winfrey’s primetime special — No One Dies Alone.

Williams' 1988 book, Eyes on the Prize: America's Civil Rights Years, 1954-65, was written with the Blackside production team as a companion to the first season of the PBS series Eyes on the Prize. His 2003 book, This Far by Faith, is also a companion to a PBS series.

Williams has contributed to a number of national magazines, including Fortune, The New Republic, The Atlantic Monthly, Ebony magazine, TIME and GQ. He has also frequented a wide range of television programs including ABC's Nightline, Washington Week on PBS, and The Oprah Winfrey Show.