Sekou Omar Doumbouya was born in 2000 in Conakry, Guinea. Doumbouya moved with his mother and three siblings to Fleury-les-Aubrais, France when he was one year old. He grew up playing soccer and started playing basketball when he was 12. By age 13, Doumbouya was already 6-foot-7. At age 14 and 15, he played parts of two seasons for INSEP, the national sports youth academy in France that produced Tony Parker, Evan Fournier, Boris Diaw and Ronny Turiaf. Teamed with future New York Knick Frank Ntilikina, Doumbouya helped France win the gold medal at the 2016 FIBA Europe Under-18 Championship and was the team's leading scorer.