J.J. Johnston (born 1925) is a Wall Street banker whose bank loaned "a lot of money" to the Revillas to help finance their drug operations, and uses his political connections to stop the police from interfering, because if the Revillas were shut down his bank would be devastated from the losses, using people like Margaret to monitor the streets, collecting information on anyone who could pose a threat, including James "Sonny" Crockett and Ricardo "Rico" Tubbs.