Joe Gomez has been at Liverpool for seven years
The 25-year-old, who joined the Reds in 2015, extends his stay at Anfield until 2027.
Gomez has made 142 appearances for Liverpool but has struggled with serious knee and ankle injuries.
"I still feel young and the best years are ahead of me. I have got more to learn and the time to do that," he said.
"I think I have the platform here to do it with the manager and the coaching staff around me and my team-mates, to make sure the best years are ahead."
The Charlton Athletic youth product has helped Liverpool win the Champions League, Premier League, FA Cup, Carabao Cup, Uefa Super Cup and Fifa Club World Cup, and made 21 appearances last season.
"One of the many wonderful things about Joe is he has experience and youth - that's not a bad combination," said Liverpool boss Jurgen Klopp.
"He has not long turned 25 but he was at the club before I was and I think after Hendo [Jordan Henderson] and Millie [James Milner] he is our longest-serving player.
"But the best thing of all is that his best years are still to come, and I could not be happier that this will happen with us."
-- Courtesy of BBC Sport