The new deal will keep Tomlin in Pittsburgh through the 2024 season.
"I am pleased to announce we have extended Mike Tomlin's contract through the 2024 season," said Steelers President Art Rooney II.
"Mike is one of the most successful head coaches in the National Football League, and we are confident in his leadership to continue to lead our team as we work to win another championship."
Tomlin, who has served as the Steelers' head coach since 2007, is just Pittsburgh's third bench boss since 1969, following Chuck Noll (1969-1991) and Bill Cowher (1992-2006).
The 49-year-old has compiled 145 wins, 78 losses, and one tie through 224 games. Tomlin led the Steelers to a Super Bowl in 2008 in just his second year at the helm.
"I am extremely grateful for this contract extension and want to thank Art Rooney II and everyone in the organization for the support in my first 14 seasons," said Tomlin. "We have a goal of winning the organization's seventh Super Bowl championship, and I couldn't be more enthusiastic about this upcoming season."
The 2021 campaign will mark Tomlin's 15th season with the franchise.
The head coach’s extension provides further stability in Pittsburgh. The club recently signed general manager Kevin Colbert to a one-year extension that will keep him around until at least the 2022 draft.