Alex Shaffer was indeed the New Jersey state high school wrestling champion the year before the film was made. However, he had to quit the sport due to a back injury.
In the movie Kyle Timmons (Alex Shaffer) is shown to be a wrestler from Ohio who starts to compete in New Jersey in order to become state champion when in actuality he himself is a real New Jersey state wrestling champion.
Amy Ryan accepted her role in this film in part because she'd played such a notoriously "bad" mom in Gone Baby Gone (2007) and thought Jackie represented a "good" mom.
The featured school, New Providence High School in New Jersey, is the alma mater of writer/director [link=Tom McCarthy].