John Feinstein, whose career as a columnist and bestselling author of sports books made him one of the most notable sportswriters of his time, died Thursday. He was 69.

Feinstein died of natural causes at his brother’s home in McLean, Virginia. Robert Feinstein said he discovered his brother’s body.

John Feinstein was a regular sports columnist for the Post but began his career as a night police reporter in 1977. He was most widely known for his coverage of college basketball, but wrote about all sports, including golf, college football and the Olympics. He wrote for Golf Digest and was a frequent contributor to a variety of radio programs, with a regular stint on National Public Radio.

“He was very passionate about things,” Robert Feinstein said. “People either loved him or hated him — and equally strongly.”

A column written by John Feinstein on Michigan State coach Tom Izzo was published Thursday morning by The Post.

Feinstein wrote 48 books, 23 of which made the New York Times bestseller list, according to his website. His first book, “A Season on the Brink,” which chronicled the 1985-86 Indiana University basketball season, made him a household name and spent 17 weeks at No. 1 on the Times’ bestsellers list. The book detailed the coaching methods of Bob Knight and was later turned into an ESPN film.

“I read “A Season on the Brink” in high school, the paperback version. Oh man, he was so good,” Texas A&M men’s basketball coach Buzz Williams said. “There’s not many left in this generation that could write the way he could in his generation.”

Feinstein also wrote “A Good Walk Spoiled,” about a year on the PGA Tour in 1994-95, that was also a No. 1 bestseller, as well as “A Civil War,” a critically acclaimed book on the Army-Navy football rivalry. He also wrote more than a dozen teen mystery books.

“The Ancient Eight,” about Ivy League football, was published last year.

“John was brilliant. He was one of the best writers for sports of all time. We were great friends. I loved John. But I knew he was polarizing,” former Duke men’s basketball coach Mike Krzyzewski said. “You loved him or hated him. He understood that. He handled it well.”

Feinstein was honored with the Curt Gowdy Media Award by the Basketball Hall of Fame in 2013. He’s also in the National Sportscasters and Sportswriters Hall of Fame.

Feinstein is survived by his wife, Christine, son Danny and daughters Brigid and Jayne, as well as Robert and his sister, Margaret.

ESPN’s Pete Thamel and The Associated Press contributed to this report.