Morant, who made All-NBA Second Team, is guaranteed $193 million and will trigger supermax escalators to take the deal to $231 million upon again landing on one of the league's three All-NBA teams.
The deal also includes a 15% trade kicker, Tanner said.
"Memphis is my home,'' Morant wrote on Twitter.
Memphis is my home 💙— Ja Morant (@JaMorant) July 1, 2022
At 22 years old, Morant has established himself as a bona fide superstar, averaging 27.4 points, 5.7 rebounds and 6.7 assists this past season.
"Over the past three seasons, Ja has truly emerged as an NBA superstar and must-see TV," Tanner told ESPN. "From Rookie of the Year, to NBA All-Star starter, to All-NBA Second Team and Most Improved Player, we are incredibly proud of him for his dedication to improving his game and developing into a team leader. The Grizzlies are a perfect fit for Ja. The organization and the city have embraced him.
"The sky is the limit for Ja both on and off the court, and we look forward to helping him continue to build his legacy in the league."
The Grizzlies tied a franchise record with 56 wins and advanced to the second round of the Western Conference playoffs this past season.
Morant won the NBA's Most Improved Player award and made the All-Star team for the first time. Along the way, he solidified himself as one of the league's most electrifying players -- and one of its best young talents -- thanks to a series of highlight-reel plays on the court and an equally outsized personality off it.
That combination has made Morant one of the young faces of the NBA, and has helped turn the Grizzlies into one of the league's most exciting up-and-coming teams, with a vast array of young talent surrounding him -- including big man Jaren Jackson Jr. and guard Desmond Bane. They locked up another player Thursday night, agreeing to a two-year, $30 million deal with free-agent guard Tyus Jones.
Despite playing in one of the league's smaller markets, Morant has blossomed into one of the league's leading endorsers, including national commercial campaigns with Sony/Spiderman and Hulu and marketing deals with Nike, Beats by Dre and Panini, among others.
After finishing second in the Western Conference this season behind the Phoenix Suns, Memphis beat the Minnesota Timberwolves in six hard-fought games in a first-round playoff series victory -- its first series win since 2015 -- before losing to the Golden State Warriors in six games in the Western Conference semifinals.
Morant, who scored a combined 115 points over the first three games of the Golden State series -- including a playoff career-high 47 points in a Game 2 victory -- missed the final three games against the Warriors with a knee injury.
The second overall pick out of Murray State in the 2019 NBA draft, Morant was the NBA Rookie of the Year in 2020. He instantly put his imprint on the franchise, and has quickly transitioned the Grizzlies from the "Grit 'n' Grind" era of Mike Conley and Marc Gasol into this new, fast-paced, run-and-gun young team under coach Taylor Jenkins.
That included Morant going toe-to-toe with Damian Lillard inside the NBA's bubble at the Walt Disney World Resorts in Orlando, Florida, as a rookie in the league's first play-in tournament game -- and then turning around and taking out the favored Warriors in San Francisco in 2021 in the play-in tournament to advance to the postseason for the first time in his career.
ESPN NBA reporter Tim Bontemps contributed to this report.