Joseph Peko is a defensive lineman from Calabasas, California, who attended Oaks Christian High School. At Oaks Christian, he played both offensive and defensive line and earned first-team All-Marmonte League honors on the defensive side as both a sophomore in 2023 and junior in 2024. As a junior, he also received All-Ventura County recognition and was named the team's defensive lineman of the year when Oaks Christian went 9-4 and reached the CIF Southern Section Division 2 semifinals. Peko earned a spot in the 2026 Polynesian Bowl and won his team's Grit Award following his senior season, though he missed part of that year due to injury. He joined Washington as a true freshman in 2026.