Financial terms of the deal announced Thursday were not disclosed. Tomlin is 82-46 with Pittsburgh since replacing Bill Cowher following the 2006 season. The Steelers have won one Super Bowl and appeared in another under Tomlin and are coming off an 11-5 mark and an AFC North title in 2014.
Steelers President Art Rooney II called Tomlin "one of the top coaches" in the NFL. Tomlin calls his time with the Steelers a "wonderful experience."
The Steelers report for training camp at Saint Vincent College on Saturday and open the preseason in the Hall of Fame game in Canton, Ohio on Aug. 9.