Brock Purdy was born in Queen Creek, Arizona.

Purdy started his varsity football career at Perry High School in Gilbert, Arizona. He played a crucial role in elevating his school's football performance, leading them to the 6A Division AIA State Championship games in 2016 and 2017.

Purdy's performances in the championship games, although resulting in losses to Chandler High School, showcased his potential as a football player.

Purdy signed his letter of intent to commit to Iowa State University on February 7, 2018.