The extension will run through the 2023-24 season.
"I'm so appreciative of Ron Burkle and Mario Lemieux, our ownership group, and (president) David Morehouse and (general manager) Jim Rutherford for showing the confidence in me to try to continue to lead this team," Sullivan said. "And so anytime that someone like myself has the opportunity to establish a little bit of stability with regard to my job, it's certainly a great help from my standpoint. I'm grateful for the opportunity that I've been given with this Pittsburgh Penguins organization. It really is a unique organization. I just think they do it right. It starts with the leadership of our ownership and it goes down from there."
Sullivan is 174-92-34 in four seasons with the Penguins, qualifying for the Stanley Cup Playoffs in each season. The 51-year-old was hired on Dec. 12, 2015, to replace Mike Johnston, and coached the Penguins to a 33-16-5 record to finish the season before winning the first of consecutive Stanley Cup championships in 2016.