The 60-year-old coach had already been under contract through 2016-17.
"He might be 60, but he's going on 35, maybe even younger than that," Louisville Athletics Director Tom Jurich said. "He's got an incredible amount of energy and he's worked extremely hard. We just love the direction this program is going."
Pitino has racked up a 275-106 record in 11 seasons at Louisville and sports a .729 winning percentage (629-234) over his entire 27-year career, ranking 11th among active collegiate coaches.
He took the Cardinals to the NCAA Tournament Final Four last season -- the sixth time he has taken a squad to that level.