Yves Missi was born in Belgium but grew up in Cameroon. He moved to the United States in 2021 and began attending West Nottingham Academy in Maryland. He later transferred to Prolific Prep in Napa, California. There he averaged 9.3 points, 8.7 rebounds and 1.3 blocks per game.
Missi played at the Nike Hoop Summit in 2023 and won the Grind Session World Championship with Prolific Prep, earning a place at the GEICO High School Nationals. He was rated a five-star prospect, and ranked by ESPN as the second-best player in California and the 13th best player nationally. He committed to play college basketball for the Baylor Bears.
In 2023-2024 for Baylor, Missi split time between power forward and center. He started 32 out of the 34 games and had a solid freshman season. He averaged 10.7 points and 5.6 rebounds, while blocking 1.5 shots per game.
Following the season, Missi announced his intentions to enter the NBA Draft.