When D'amato was 22 years old, he opened the Empire Sporting Club with Jack Barrow at the Gramercy Gym. D'amato was very dedicated to the gym and even lived there for three years. D'amato spent his time at the gym waiting for a champion to train. D'amato believed that psychological training was more important than mental training and many boxers, like famous heavyweight champion Mike Tyson (who D'amato trained) credit his style of training and belief in his athletes as a big reason for their success. D'amato, however, lost many of his boxers due to his resistance against the IBC (International Boxing Club) by not allowing his fighters to compete in any match sponsored by the organization which was eventually found out to be in violation of anti-trust laws and was stopped.
D'amato created a style of boxing called Peek-A-Boo. This style consisted of the boxer's hands being placed in front of their face. It allows for extra protection for the fighter all while making it more accessible to jab the opponent.
D'amato was an influential trainer and trained some of the most famous and successful boxers in the world. These include Joey Hadley a professional boxer who won the Golden Gloves six times and used D'amato's Peek-A-Boo style when fighting. Also, Floyd Patterson who was the first boxer to use the Peek-A-Boo method effectively to become an Olympic gold medalist and a 2-time heavyweight champion of the world. His most famous trainee, however, was Mike Tyson who D'amato cared for and basically raised when Tyson's mother died at 16, even becoming his legal guardian.