The team announced the completion of the deal, and Booker tweeted about it as well.
I am humbled & honored to commit to the Suns organization long term. I loved calling Phoenix home the last 3 seasons as this team & community are special to me. Thank you to the Suns for drafting me and believing in me. I look forward to the future & pursuing a title as a Sun. pic.twitter.com/AHRaraPww6— Devin Booker (@DevinBook) July 8, 2018
Booker, 21, has rapidly developed into the Suns' cornerstone star and the franchise's hope to lead it out of the lottery and back to the NBA playoffs.
In 2017, Booker became the first player in franchise history to score 70 points, doing so against the Boston Celtics in a March 24 game. Booker was 20 years, 145 days old at the time of his 70-point night, making him the youngest player in NBA history to score 60 or more points in a game.
Booker averaged 24.9 points per game in his third NBA season. He has been general manager Ryan McDonough's most decorated draft pick in Phoenix, taken as a freshman out of Kentucky who dropped to No. 13 in the 2015 NBA draft.
Booker, who in a video posted by the team on Twitter said "the future is here," has been surrounded with three lottery picks in the past two drafts by the Suns, including this year's No. 1 overall pick, center Deandre Ayton, No. 10 pick Mikal Bridges and 2017 No. 4 overall pick Josh Jackson.
ESPN's Adrian Wojnarowski reported Tuesday that the sides were progressing toward finalizing the deal, with the Suns presenting the offer to Booker in Los Angeles that day, according to sources.