McCaffrey made two starts for the Cornhuskers in 2020 and appeared in five of Nebraska's other six games. He redshirted his first year on campus.
At Louisville, McCaffrey will join a quarterbacks room that features multi-year starter Malik Cunningham. The senior-to-be was inconsistent last year but has shown promise in the past.
McCaffrey completed 57 of 88 career pass attempts for 608 yards, three touchdowns, and six interceptions at Nebraska. He also rushed for 530 yards and four scores.
He's the son of longtime Denver Broncos tight end Ed McCaffrey and the younger brother of Carolina Panthers star Christian McCaffrey. One of his other brothers, Dylan, is transferring to Northern Colorado after beginning his college career at Michigan.