J.J. Watt is 35 years and 8 month(s) old. He was born in 22 Mar, 1989. Justin Watt is a famous American Football player. He is 6 feet and 5 inches tall and Justin is also one of the best defensive players in the history of America. At present, he is battling an injury that he received in 2015. He also underwent a couple of surgeries to recover.