In doing so, he became the first player in NBA history to lose the first three games in which he scored 50 points, according to the Elias Sports Bureau. He also became the youngest player in NBA history with consecutive 50-point games.
Booker, who scored 59 in a loss to the Utah Jazz on Monday night, was 19-of-29 from the field against the Wizards and had 10 rebounds with his 50 points.
"It's a blessing. It's an honor, I say it every day, to lace it up and play a sport that I love," Booker said. "I think right now it's time for me to be more aggressive, being down a couple of men. Teammates helping me, setting good screens. ... Fell short, but a lot better fight today than we did have in the last game."
He is the seventh player to record 50 points in consecutive games since the NBA-ABA merger (1976-77), according to ESPN Stats & Information. He joins James Harden, Michael Jordan, Kobe Bryant, Bernard King, Antawn Jamison and Allen Iverson.
Booker also became the third player in NBA history to score at least 50 points in consecutive games and lose both, following Harden and Wilt Chamberlain.
"Devin is just -- he takes so many shots that are almost like, they're unguardable," Wizards coach Scott Brooks said. "We did the best we can. We were trying to trap him and double-team throughout the game. He's crafty. He was attacking us."
At 22 years, 149 days old, Booker is the fifth player in NBA history to record three 50-point games before turning 25, putting him in the company of Chamberlain, Rick Barry, Kareem Abdul-Jabbar and LeBron James. Of those players, only James was younger than Booker at the time of his third 50-point game.
Wednesday marked the first time a Phoenix player reached 50 in back-to-back games. Tom Chambers had been the only member of the Suns to score even 40 in successive games.
"The fans in Phoenix have been behind us the past four years since I've been here," Booker said. "They deserve that. It's entertainment for them. They come to the game, and hopefully I try to put on a show for them and hope they enjoy and make memories that last forever."
The Suns, who have the worst record in the Western Conference at 17-59, also saw center Deandre Ayton break Alvan Adams' franchise record for most double-doubles in a rookie season (37). Ayton finished with 14 points and 10 boards Wednesday night.
The Associated Press contributed to this report.