Kathryn Erbe's pregnancy was incorporated into the show by having her character Alexandra, be a surrogate mother.
The show is filmed in Chicago. The actors/actresses trained for 3 months beforehand with retired S.W.A.T. personnel and real Chicago Police officers.
Julianna Margulies wore a wig for her character Alicia
Eli Gold, played by Alan Cumming, is modeled after Chicago politician Rahm Emanuel, former chief of staff of president Barack Obama.
While all the fly-over shots, skylines and cityscapes really are of Miami, Florida, any beach scenes during the series, were filmed at Manhattan Beach, a suburb of Los Angeles.
Chicago P.D. is one of the few shows that is produced with the approval of the Chicago Police Department. The show has permission to use accurate uniforms, insignia, and markings.