The character of Detective Robert Goren (Vincent D'Onofrio) is based on the popular fictional character of Sherlock Holmes, but instead of relying upon physical evidence like Holmes, Goren focuses on psychology to identify the perpetrators, whom he often draws into confessing or yielding condemning evidence. Goren also works with a John Watson like partner in Detective Alexandra Eames (Kathryn Erbe) and works for Inspector Lestrade type commanding officers Captain James Deakins (Jamey Sheridan) and Captain Danny Ross (Eric Bogosian) The character of Nicole Wallace (Olivia d'Abo) is a direct attempt to play on the part of Sherlock Holmes' female antagonist Irene Adler, also known as "The Woman". Wallace is employed as a "Professor of Literature" during her first appearance, which could be a parallel to Holmes' nemesis Professor Moriarty.
At the end of the fourth season, Jamey Sheridan suffered Bell's palsy, a facial paralysis that affected one half of his face. In the fifth season, his character, Captain James Deakins, carried an eye patch over his left eye, to hide the signs of the paralysis.
The following statement appears at the beginning of each episode: "In New York City's war on crime, the worst criminal offenders are pursued by the detectives of the Major Case Squad. These are their stories." This is the only Law & Order series where the opening statement does not begin with the words "In the criminal justice system..."
The show's format was partially inspired by Columbo (1971), starring Peter Falk. Both started out with the crime being seen from the criminal's point of view, and with them confident that they can get away with it. However, they then get outsmarted by a brilliant detective. The shows differ, in that "Columbo" usually showed the full crime in the beginning, while in this show, the viewer is only shown enough to be a few steps ahead of the detectives in knowing what happened. Goren and Columbo also have very different styles in analyzing the crime, and the suspects.
Vincent D'Onofrio and Chris Noth have both played the role of Phil Romano in That Championship Season, the former in the 1999 film, and the latter in the 2011 Broadway revival. In an earlier film version, the part was played by Paul Sorvino, Noth's co-star on the original Law & Order (1990).