Creator Shawn Ryan's original title of the show was "The Barn". The FX network feared that potential audiences might be turned away by that, because they might think it was a gardening show or something similar. "Rampart" was also considered, after the controversial corruption charges against the Rampart division of the Los Angeles Police Department. This title was used in early promotional materials, including several TV spots. Upon opposition from the LAPD, as well as the fact that people not familiar with the Rampart scandal might not understand the name, the title was changed at the last minute to "The Shield".
FX originally balked at the hiring of Walton Goggins as a regular cast member. In order to convince the network executives to hire him, the episodes "Our Gang" and "The Spread" were specifically rewritten in order to showcase Walt's acting abilities in hopes of him being hired as a full-time cast member. These episodes convinced FX to give the go-ahead to hire him as a full-time cast member though because of the delays in finalizing his contract, the Shane character was written out of three episodes with the Vic Mackey character partnered up with fellow cast member Kenny Johnson ("Dawg Days" and "Throwaway") or assisting Detectives Wyms and Wagenbach on case ("Cherrypoppers").
Shawn Ryan originally wrote Claudette's character as a man. It took a call from CCH Pounder's agent to make him appreciate a woman detective would offer a whole new slant to proceedings. One thing that Ryan didn't change though was the dialog, meaning that Claudette pulls no punches with her fellow detectives and the criminals she encounters. This was at Pounder's request.
In the original pitch of the series to FX, the members of the Strike Team were supposed to be background characters and that the character of Vic Mackey would mainly interact with the other characters. However, after casting David Rees Snell and Kenny Johnson as members of the Strike Team, it was decided to make the Strike Team members a regular part of the series.
The uniformed officers originally wore realistic LAPD-style badges over their left breast, which is standard in the real Los Angeles Police Department, as it is symbolically over the heart. After criticism from the real LAPD over the show's depiction of corrupt cops, the badges were replaced with less realistic badges which were worn over the right breast, starting midway through the first season.
When the show started airing, creator Shawn Ryan would notice that people were divisive regarding whether they like Vic Mackey or not and some wanted him to get caught. When Lt. Jon Kavanaugh was introduced into the storyline as a serious possibility for Mackey to go down, Ryan was surprised to learn that almost everyone rooted for Mackey and hated Kanavaugh.
Prior to the start of the series, star Michael Chiklis had been known mostly for playing the chubby, good natured title character on "The Commish" (1991). Because of the contrast between that characters laid back, affable style, and Vic Mackey's violent and brutal style, Mackey was often referred to in the descriptions of the first season as "The anti-Commish."
According to Michael Chiklis , Jay Karnes had difficulty believing Dutch would be afraid of fighting Vic due to his size advantage. Karnes is 6'2" while Chiklis is 5'8". They debated for a while until Chiklis convinced Karnes that Dutch was afraid of Vic's violent temper.
Shawn Ryan has declared several times that at one point it didn't really make sense to keep the character of David Aceveda on the show, but they figured out a way to do so because they loved working with Benito Martínez.
On the back of Vic's car you can sometimes see a ManCow sticker, this is in reference to a Chicago radio show host who is good friends with Michael Chiklis. ManCow has also appeared as stand-ins for police line-ups on the show.
According to Glenn Close, she based a lot of her performance as Monica Rawling on a real police captain from New York named Theresa J. Shortell and actually spoke to Shortell during the broadcasting for feedback.
Michael Chiklis (Vic Mackey), who played the leader of The Barn's Strike Team, would go on to join the cast of Fox's TV series Gotham for its second season as Captain Nathaniel Barnes where he and Detective James Gordon (Ben McKenzie) put together a crime fighting team called the Strike Force.
The trivia items below may give away important plot points.
Michael Chiklis claimed that while filming the ending of Season 1 when Vic breaks down, he suffered a genuine panic attack from the force of his performance, and that clutching his chest was not acting.
In the series finale, the federal agent (Clark Johnson) mentions that the Burpee Museum is only a few blocks from Corrine's new home. The Burpee Museum is located in Rockford, IL, the birthplace of Shawn Ryan.