Brown attended Wheeler High School in Marietta, Georgia.
As a senior, he helped lead his team to victory in the Georgia High School Association (GHSA) Class 6A State Championship.
With 0.6 seconds remaining, Brown hit two free throws to give Wheeler a 59–58 win.
more highlights of brown's senior season include scoring 28 points and 11 rebounds in a 76–70 win against Harry Giles and Wesleyan Christian Academy, a 24 points and 8 rebounds in a 61–40 win over Malik Monk and Bentonville High School, 25 points, 12 rebounds and 6 assist in a 75–65 win over Ben Simmons and Montverde Academy, and 29 points and 15 rebounds against Huntington Prep.
As a senior, Brown averaged 28 points and 12 rebounds while leading Wheeler to a 30–3 overall record.

Brown was rated a five-star recruit and ranked by Scout.com, ESPN, and 247Sports.com as the fourth best recruit in his class behind Ben Simmons, Skal Labissière, and Brandon Ingram.
Rivals.com ranked him third in his class.

Brown won a 2014 FIBA Americas Championship gold medal as part of the USA Basketball Men's U18 National Team.
He was also selected to play in the 2015 McDonald's All-American Boys Game.
At the conclusion of an outstanding high school career, Brown was named Gatorade Georgia Boys Player of the Year, USA Today's All-USA Georgia Player of the Year, Georgia's Mr. Basketball, and the Class 6A Player of the Year.
Brown attended Wheeler High School in Marietta, Georgia. As a senior, he helped lead his team to victory in the Georgia High School Association (GHSA) Class 6A State Championship. With 0.6 seconds remaining, Brown hit two free throws to give Wheeler a 59–58 win. more highlights of brown's senior season include scoring 28 points and 11 rebounds in a 76–70 win against Harry Giles and Wesleyan Christian Academy, a 24 points and 8 rebounds in a 61–40 win over Malik Monk and Bentonville High School, 25 points, 12 rebounds and 6 assist in a 75–65 win over Ben Simmons and Montverde Academy, and 29 points and 15 rebounds against Huntington Prep. As a senior, Brown averaged 28 points and 12 rebounds while leading Wheeler to a 30–3 overall record.
Brown was rated a five-star recruit and ranked by Scout.com, ESPN, and 247Sports.com as the fourth best recruit in his class behind Ben Simmons, Skal Labissière, and Brandon Ingram. Rivals.com ranked him third in his class.
Brown won a 2014 FIBA Americas Championship gold medal as part of the USA Basketball Men's U18 National Team. He was also selected to play in the 2015 McDonald's All-American Boys Game. At the conclusion of an outstanding high school career, Brown was named Gatorade Georgia Boys Player of the Year, USA Today's All-USA Georgia Player of the Year, Georgia's Mr. Basketball, and the Class 6A Player of the Year.
Jaylen Brown