Pitino had three years left on his previous contract.
Reports have said he will be paid a base annual salary of $2.25 million.
In 21 seasons as a college coach, Pitino has an overall record of 494-182 at Louisville, Kentucky, Boston University and Providence. His teams have qualified for five NCAA Tournaments, and he led Kentucky to the NCAA title in 1996.
"Rick has meant so much not only to our men's basketball program, but to this community," said Louisville Athletic Director Tom Jurich. "He obviously has Hall of Fame credentials and I'm thrilled that we can count on him guiding our men's basketball program for at least the next six years."
Louisville was 24-10 (12-4 Big East) last season, and lost to Texas A&M, 72-69, in the NCAA Tournament's second round.
Pitino also coached the NBA Boston Celtics for 3 1/2 years.
Notable deaths of 2014 [PHOTOS]
Julius Randle breaks leg during NBA debut