In the summer of 2018, he transferred to Orange Lutheran High School in Orange, California. As a junior, he earned All-Trinity League first team and Orange County Register All-County second team honors. Maker faced eligibility questions entering his senior season, because he had already exhausted his eight semesters of eligibility. Instead of seeking a waiver from the California Interscholastic Federation to continue playing for Orange Lutheran, he transferred to Pacific Academy, a prep school in Irvine, California, and continued his career with the affiliated program, Center of International Basketball Academy. On October 17, 2019, it was announced that he had submitted paperwork to explore his eligibility for the 2020 NBA draft. On 18 December, Maker transferred to Hillcrest Prep in Phoenix, Arizona for the remainder of the season. On 25 April 2020, he declared for the 2020 NBA draft. Despite finishing two credits short of high school graduation, Maker was granted eligibility by the NBA. However, on 3 August he withdrew from the draft to play college basketball.