|Other family||Manuel Calderon (brother)|
|Appearances||"Anatomy of a Murder"|
|Portrayed by||A Martinez|
Calderon was a former drug lord who had moved to New York to retire, currently living in a penthouse with his brother Manuel. He was a fan of Richard Castle's novels, commenting that he read them when he sought a return to his glory days, being particularly fond of the Nikki Heat series, although he only read the Spanish translations because he felt they were superior.
Six months prior to his encounter with Castle and Beckett, Calderon had a heart attack and was brought to County General Hospital, where he became close to Doctor Valerie Monroe, asking her to become his personal physician. She spent five nights a week at his penthouse to see to his care, with their relationship becoming close over the following months, although Calderon denies that there was ever any physical romance in their relationship.
Beckett and Castle came to question him when Monroe was found dead after receiving an injection of air directly into her carotid artery, causing her to suffer an aneurysm, but Calderon's alibi that he was at home in his penthouse at the time of the murder checked out. However, they later discovered that Manuel had actually killed her, believing that Monroe was working with the attorney general to investigate Cesar but in reality she had been investigating drug theft at the hospital.