The East 25th Street entrance of the William and Anita Newman Vertical Campus of Baruch College in the Gramercy section of Manhattan served as the entrance façade of All Saints Hospital at which Nurse Jackie and her colleagues work during the first three seasons. In the fourth season, the hospital's entrance façade was changed to Bellevue Hospital at East 27th Street and First Avenue.
Although they have stated from the very beginning that it wouldn't happen, co-creator Linda Wallem said they decided to get Jackie into rehab mainly because Edie Falco shared some concern about the character's influence. According to Falco, many people came up to her on the street and said, with excitement, that they used the same drugs as Jackie.
The character played by Haaz Sleiman during the first season of the show was nicknamed Momo, but his actual name is Mohammed de la Cruz. Both his first and last names are essential elements of two different major world religions (Mohammed is the inventor of Islam, and "de la Cruz" means of the cross in Spanish, the cross being a foundational symbol of Christianity).