Leunen led Redmond to the state championship in 2003, where they beat Hillsboro High School 50–47 at Portland's Memorial Coliseum.

In 2004, he led Redmond to the state championship game but the team fell short, losing to South Salem High School 54–43 at Eugene's McArthur Court.

His post defense, rebounding and offensive versatility (namely his ability to shoot the three and run the floor) created problems for opponents all season long.

[11] On August 1, 2018, Leunen's draft rights were traded back to the Houston Rockets in exchange for Chinanu Onuaku with the 2020 second-round pick and cash considerations.

[12] On February 7, 2019, Leunen's draft rights, along with Nik Stauskas and Wade Baldwin IV, were traded to the Indiana Pacers in exchange for cash considerations.