As a junior at Malvern Preparatory School, Hornibrook would study extra film and conduct offensive meetings without the help of a coach.

[8] Inconsistent non-conference play cast scattered doubts on Hornibrook's ability early in the season,[14] but still performed at a serviceable level.

[16] In the 2017 Orange Bowl against the Miami Hurricanes, Hornibrook was named the game's MVP after throwing four touchdowns[17] completing 23 of 34 pass attempts, finishing off a 13–1 season.

[22] Hornibrook's relatives have played collegiate athletics or professionally in football, baseball, water polo, basketball, swimming and lacrosse.

[3] His brother, Jake, was an offensive lineman for Stanford, his sister, Mackenzie, was a captain of the Penn State swimming and diving team, his father, Jeff, was an offensive lineman for the Temple Owls, his mother, Dawn, played basketball at Gettysburg College, his uncle, Ben Davis, was the second overall pick in the 1995 MLB Draft and had an eight-year long MLB career, his aunt, Megan Davis, played both soccer and lacrosse at Rutgers, and his great uncle, John, played quarterback for the Miami Hurricanes.