Paramedics responded to a call from Noll's wife, Marianne, at 9:45 p.m. ET when she found him unresponsive. Noll was declared dead 10 minutes later.
The Allegheny County Medical Examiner said he died of natural causes.
Noll was reported to be under a doctor's care for an undisclosed illness. He had been suffering from back pain and heart issues, among other problems in recent years.
As coach of the Steelers from 1969 to 1991, Noll guided the franchise to Super Bowl wins in the 1974, 1975, 1978 and 1979 seasons. In those 23 seasons, he compiled a 209-156-1 record.
When Noll took over, the Steelers had won only 18 games in five seasons. In his first year, the Steelers finished 1-13, but the turnaround had begun. Three years later, the Steelers reached the AFC championship game and two years after that they won their first Super Bowl.
After Noll retired, he was elected to the Pro Football Hall of Fame in his first year of eligibility.
Born in Cleveland, Noll played football at the University of Dayton and was drafted by the Browns in 1953. He remained with the Browns until he retired at age 28 in 1959 to take a coaching job at Dayton. But he was hired instead by Chargers coach Sid Gillman and remained there for six seasons.Copyright © 2015, The Baltimore Sun