Lambo, who signed the contract with his wife and two dogs beside him, confirmed the deal on social media. Sources told the NFL Network that the deal is worth $15.5 million with $6.5 million in guarantees.
Lambo connected on 19-of-21 field goal attempts last season as the Jaguars finished with a 5-11 record. He converted 4-of-5 attempts from 50 or more yards, and made 19-of-20 extra points.
The 28-year-old Lambo went undrafted and signed with the then-San Diego Chargers in 2015. He played two seasons with the Chargers before joining the Jaguars in October 2017.
"I'm not quite sure it has set in yet," Lambo told the team's official website. "This whole NFL journey has been a little wild and very unexpected. Now that I've gotten to a point to where I can sign an extension with this club, it's really special."
Lambo signed the deal at a dog park located inside TIAA Bank Field. His wife, Megan, and their two dogs participated in the event, including the dogs marking the contracts with their paws.
"It's a great day for myself, Megan and my dogs, and the whole family," Lambo said. "It's kind of a statement for just what my life is. Obviously, my wife is here, and my dogs, because I wanted them here. It's a big day for me, so it's a big day for them."
Lambo has converted 38-of-41 field goals and 41-of-44 extra points in 23 contests with Jacksonville. He was scheduled to become an unrestricted free agent March 13.