Clarke was born in 1996 in Vancouver, British Columbia, Canada and moved to the United States at the age of three. He was one of Arizona's top shot-blockers when attending Desert Vista High School in Phoenix. Clarke was able to lead the team to the Division I state championship in 2015. As a senior, he was named to the first-team All-Arizona Division I by the Arizona Republic, having recorded 10 triple-doubles. As a junior, he averaged 15.0 points, 7.0 rebounds, 4.0 assists and 4.0 blocks. Check out Clarke on Twitter (@brandonclarke23) and Instagram (@brandon_clarke23).