Knight attended Ronald Reagan High School in San Antonio, Texas. While at Ronald Reagan High School, he played for the football team. As a senior, he threw for 2,092 yards and 27 touchdowns with 943 rushing yards and 15 touchdowns. He was ranked as the sixth-best dual-threat quarterback recruit by the Rivals.com recruiting network. Trevor has a fraternal twin brother, Connor, who was a longsnapper/fullback for Oklahoma. They played alongside each other for Trevor's entire time with the Sooners; however, Connor elected to stay at OU when Trevor transferred to Texas A&M.
