Sources told ESPN the contract is worth $40 million over three years and includes a player option before the 2023-24 season. Kuzma, 25, finalized talks on his extension Sunday, sources said.
In a rare non-max rookie extension that includes a player option, the deal allows for Kuzma to become an unrestricted free agent in his prime at 28 years old. That's a benefit should Kuzma outperform his extension, which starts with the 2021-22 season.
He is competing for a starting job on the Lakers, who will begin defense of their NBA title on Tuesday night against the LA Clippers at Staples Center.
In his first three NBA seasons with the Lakers, Kuzma started 114 games and averaged 16.0 points. He was the 27th overall pick in the 2017 NBA draft.
"I mean, it's good for him," teammate Anthony Davis said Sunday. "You don't have that contract anxiety for the whole year. Now that it's out of the way, you can go out there and play, which he was doing anyway. He was having a great preseason. He's been playing great for us in the bubble and all of last year. He's locked in. He made a great jump on both ends of the floor.
"So, it's good for him. We're excited to have him here. I know he's excited to be here. And he's a champion. You deserve it. I'm glad that the Lakers were able to work something out with him to be able to allow him to just go out there and play and not worry about contracts for the rest of the season."
The deadline for signing rookie contract extensions for the 2017 draft class is Monday night, the eve of the start to the regular season.
Information from ESPN's Dave McMenamin was used in this report.