"It's exciting. It's where I want to be," Guentzel said. "I think it's a top-notch organization from all the way down, the best players and coaches. So definitely the place I want to be and I'm happy to get it done."
The 24-year-old forward could have become a restricted free agent July 1.
"I think whenever you can get it done and just focus on playing now," Guentzel said. "So it's always nice and with an organization like this, they made it pretty easy on me."
Guentzel is third on the Penguins this season with 15 goals, one behind Sidney Crosby and Phil Kessel.
Selected by the Penguins in the third round (No. 77) of the 2013 NHL Draft, Guentzel has 114 points (53 goals, 61 assists) in 159 regular-season games.
"It starts with the fans. They're second to none," Guentzel said. "They're there every night for us. So it starts with them. The coaching staff is phenomenal and gets better every day. I think the ownership and management set the bar really high. So I'm really happy to be here and it'll be a good five years."
He helped the Penguins win the Stanley Cup in 2017 with a playoff-high 13 goals, and has 42 points (23 goals, 19 assists) in 37 Stanley Cup Playoff games.
"Jake established himself as an impact player for our team from the beginning, especially during 2017 Stanley Cup Playoffs," Penguins general manager Jim Rutherford said. "He has become a core player on the team and we are thrilled to get Jake signed long-term with the Penguins."
NHL.com correspondent Wes Crosby contributed to this report
