Luke is the youngest son of longtime NFL receiver Ed McCaffrey. The dual-threat quarterback is the 149th-ranked prospect in ESPN's 2019 cycle, and is the top-ranked player from Colorado.
He credited new Nebraska head coach Scott Frost and his staff as the key factor that led to his commitment.
"I feel great (about the coaches)," McCaffrey told 247 Sports' Mike Schaefer. "That was a big reason for this decision. I love the way that coach (Mario) Verduzco looks at the quarterback position and he will help me grow as a player greatly."
"It was definitely the right system. And the culture that the coaches are trying to create really appeals to me. And overall, it was the best fit all around."
Luke's older brother, Christian, is a running back who was the Carolina Panthers' first-round pick in 2017. His eldest brother, Max, played wide receiver at Duke and is on the San Francisco 49ers' training camp roster, while his other brother, Dylan, is currently a quarterback at Michigan.