Patrick Wade, the director of the Pat Summitt Foundation, confirmed the Mannings' decision Saturday after it was first reported by CBS Sports.
The commitment by Peyton and Ashley Manning represents the largest gift announcement made to the foundation since it was founded in November 2011 to help fight Alzheimer's disease. Manning, who played at Tennessee from 1994-97, is an honorary co-chair of the foundation's advisory board.
Summitt stepped down as the Tennessee women's basketball coach last April after announcing in 2011 she had early-onset dementia, Alzheimer's type. She went 1,098-208 and won eight national titles in 38 seasons. Summitt remains on Tennessee's staff as head coach emeritus.