Writer and director Dito Montiel was reluctant to cast Shia LaBeouf in the role of young Dito because Montiel was intent on casting an unknown. After the first rejection, however, LaBeouf pushed for one more audition. He came into the casting office, punched a hole in the wall, and convinced Montiel that he could bring the requisite amount of anger to the role.
Many of the locations used in the film were the same places where the actual events had occurred. The conversation between Dito and Flori in the early morning for example is down the street from where the real Antonio had lived. Dito Montiel joked that many of his childhood friends would hang around the set for filming, and tell the cast members "I never would have said that."
Shia LeBeouf and Channing Tatum only had one day to get to know each other, despite playing childhood friends. They decided to go out and get drunk on the streets of New York City. They remain good friends to this day.
Robert Downey, Jr. had originally planned to direct the film himself. But in the four years of pre-production, he became busy with various other projects. Eventually Dito Montiel decided to direct, despite having only made a couple of short films beforehand. Robert Downey, Jr. remained on as a producer.
Channing Tatum lost "a lot of weight" to play Antonio, at his own suggestion. Dito Montiel said that Tatum was a little too good looking to be Antonio, but ultimately brought the right amount of emotion for the character.