Barnett has said that he admitted to himself that he was gay when he was 13 years old.
Barnett has admitted to struggles with alcohol addiction.
Barnett was a class of 2010 graduate of the drama program at the Juilliard School in Manhattan, New York City, New York, USA.
His hobbies include sailing, playing Ms. Pac-Man, and classic cars.
During his time as a regular cast member (2012-2015) on Chicago Fire (2012), Barnett was roommates with cast mates Joe Minoso and Yuriy Sardarov. He is a White Sox and Chicago Bears fan.