Guentzel was set to be a restricted free agent following the season, but the latest contract kicks in next year and will run through 2023-24.
"Jake established himself as an impact player for our team from the beginning, especially during 2017 Stanley Cup playoffs," general manager Jim Rutherford said in a statement. "He has become a core player on the team and we are thrilled to get Jake signed long-term with the Penguins."
The 24-year-old is in his third year with the Penguins and ranks fourth on the team with 33 points in 36 games. He has 15 goals, which gives him a good chance to set a new personal best after scoring 22 times last season.
He first came up in 2016-17 and became a key player down the stretch, but he became a household name during the playoffs. Guentzel scored a league-best 13 goals to go with eight assists while helping Pittsburgh win its second straight Stanley Cup title.
Guentzel has remained a valuable part of the offense and has consequently earned himself a new deal with an average annual salary of $6 million per year.
With the way this core is built, the extension could help the Penguins remain in title contention for another few years.
Meanwhile, Guentzel is one of the rare young stars on an otherwise aging team. Sidney Crosby, Evgeni Malkin, Kris Letang and plenty of others are already over 30 and won't be on the roster forever.
The latest signing could not only help Pittsburgh extend its championship window but also make a new face of the franchise going forward.