Jenkins was born and raised in Fort Worth, Texas, where he attended R. L. Paschal High School and Texas Christian University (TCU), where he played on the varsity golf team. Jenkins has worked for many publications including the Fort Worth Press, Dallas Times Herald, Playboy, and Sports Illustrated, where among other things he covered the 1966, 1967, 1969 and 1971 versions of the college football Game of the Century. In 1985 he retired from Sports Illustrated and began writing books full-time, although he maintains a monthly column in Golf Digest magazine.

Larry King has called Jenkins "the quintessential Sports Illustrated writer" and "the best sportswriter in America." Jenkins has written numerous works and over 500 articles for Sports Illustrated. In 1972, Jenkins wrote his first novel, Semi-Tough. Jenkins now lives in Fort Worth with his family. His daughter Sally Jenkins is a Sports columnist for the Washington Post.

In December 2014, Jenkins published an article in Golf Digest titled "My (Fake) interview with Tiger; or how it plays out in my mind." In the piece, which featured images of a Tiger Woods lookalike in golfing gear, Jenkins mocks Woods' reputation in an imaginary interview with the athlete. Though the piece was clearly marked as parody, the champion Golfer requested an apology from the magazine. Woods stated that the piece "fails as parody, and is really more like a grudge-fueled piece of character assassination."