Letang was a pending unrestricted free agent later this month. His new deal begins in 2022-23 and runs through 2027-28.
"Kris epitomizes what it means to be a Pittsburgh Penguin," Hextall said in a statement. "The role he plays on our team is irreplaceable, he is a leader in our locker room, and has made countless contributions to the organization over the last 15-plus years, which includes three Stanley Cup championships. We are thrilled to make him a Penguin for life."
Letang, 35, has spent his entire career with the Penguins in a prominent top-four role. Pittsburgh drafted him in the third round, 62nd overall, in the 2005 NHL entry draft, and he now leads all franchise defenseman in most games (941), goals scored (144), assists (506) and points (650).
Letang is also a three-time Cup winner with Pittsburgh, earning titles in 2009, 2016 and 2017. His postseason totals -- 149 games, 23 goals, 67 assists and 95 points -- are most ever by a Penguins defenseman.
Getting Letang locked up on a relatively team-friendly deal is good business for him and the Penguins. Pittsburgh has limited cap space to address a few key free agents -- including center Evgeni Malkin -- and offering Letang a longer-term deal makes up for a potentially lower salary than he could have fetched on the open market.
In addition to Malkin, the Penguins also have Rickard Rakell and Evan Rodrigues coming up on free agency this month. Starting goaltender Tristan Jarry is entering the final season of his deal as well, making it all the more important Hextall be prudent now with what space he has to work with.