"This is a guy who has taken the ball every Friday night since he showed up at LSU as a freshman," Cubs director of player development and scouting Jason McLeod said in June. "He's been one of the better performers, one of the better competitors, pitching in the best conference in the country for three years."
MLB.com ranked Lange as the 23rd-best prospect prior to the Draft.
The Cubs also signed their fifth-round pick, outfielder Nelson Velazquez, and sixth-round selection, pitcher Jeremiah Estrada.
Overall, the Cubs signed 29 picks from the Draft, including the first 22 selections.