Sain had a stroke in 2002 and had been in poor health. The Knollcrest Funeral Home in Lombard, Ill., said it was handling the arrangements.
The Chicago Tribune reported Sain's death earlier on its Web site.
He became the first Brave to record three consecutive 20-win seasons, and the third of those seasons came in 1948, when Sain helped lead the Braves to the World Series.
The man once nicknamed "A Man of a Thousand Curves" may have been a household name for the Braves during the team's final years in Boston, but his journey to the Majors was a circuitous one.
Signed by the Detroit Tigers as an amateur free agent in 1936, Sain labored through the Minor Leagues until he cracked into the big leagues in 1942. His path to Boston included spots in numerous southern leagues where the pitcher also spent some time playing as an outfielder.
After pitching out of the bullpen for Boston in 1942, the Havana, Ark., native took a three-year hiatus from baseball to be a test pilot for the Navy during World War II. When Sain returned in '46, he began a string of six years in which he notched five 20-win seasons.
He was a pitcher known for control and durability, one who would carry around books about positive thinking and often spit out quotes from the texts he read.
Spahn and Sain would become one of the most feared pitching duos of their time. From 1946-50, the pair won 153 games, which accounted for a remarkable 46 percent of the Braves' wins during that period.
Sain was three-time All-Star, with his most dominant season coming in 1948. During that year, he led the National League in wins (24), complete games (28) and innings (316) while posting an impresssive 2.60 ERA.
During a disappointing five-win season with the Braves in 1951, Sain was traded to the Yankees, for whom he was a member of three more World Series championship teams before retiring with 139 career wins.
But even as excellent as Sain was on the mound during his 11-year career, he is remembered even more so for his work as a pitching coach.
His coaching presence was much like his pitching, fluid and durable and always in control. His pitchers swore by his philosophy and for good reason. Sain went on to develop 16 20-game winners during a 17-year span in the '60s and '70s.
Sain served as a coach on six different Major League clubs, including a stint with the Yankees in the 1960s and then with the Braves in 1977 and 1985-86.
Denny McLain, Whitey Ford and Jim Kaat were three of those pitchers who thrived under the supervision of Sain, who encouraged his pitchers by telling them: "Don't be afraid to climb those golden stairs."
The pitching coach's formula for success was a simple one. Mentor, don't dictate; emphasize the positive, avoid harping on the struggles. He gave advice and suggestions, but never orders.
"Johnny Sain is the greatest pitching coach -- ever," said Jim Bouton, one of Sain's successful pupils. "I admire him more than any man I've ever met. All players like him: white, black, conservative, liberal, loud, quiet, they all do. Johnny Sain gets a pitcher's allegiance before any manager."
Sain's coaching philosophy was grounded in the psychological aspect of a pitcher. Pitching, he said, required not only a physical skill, but also a maturity that separates a pitcher from any other position player.
"There are only two men on the diamond who cannot lose their composure, who must remain above things," Sain once said. "Those are the manager and the pitcher. A batter can kick and scream and fielders can get mad. But when a manager or a pitcher loses his composure, the advantage swings to the other side. There is so much of it that's psychological. I can't stress enough how important that is."
In addition to developing pitchers, Sain mentored a young coach by the name of Leo Mazzone, who followed in Sain's footsteps by developing myriad 20-game winners of his own.
Mazzone soaked up every word.
"Sain was the first guy I had been around that didn't just have the same clichés," Mazzone once said.
Sain advised Mazzone to make his pitchers throw twice in between starts and stressed movement more than velocity in a pitcher's pitches.
"I've always felt a lot of pitching coaches made a living out of running pitchers so they wouldn't have to spend that same time teaching them how to pitch," Sain said in 1972.
Sain spent that time teaching his pitchers how to pitch. And by the time he stepped away from baseball, he had taught it as well as any pitching coach in the history of the game.