During filming, actor Al Pacino frequently ad libbed and improvised. Pacino like to do this because he was slow learning lines as well as to be spontaneous. This however can interfere with another actor's performance. Reportedly, Pacino's mentor, Lee Strasberg, said "Al, learn your lines, dollink!". Pacino years later recognized that this was good advice.
The film is famous for its line "You're out of order! You're out of order! The whole trial is out of order! They're out of order!". The line of dialogue has been frequently referenced and parodied in popular culture.
On and off the set, Al Pacino was seen frequently being "in character" due to his method acting, something to which he had been a student of under co-actor Lee Strasberg. At meal breaks, Pacino would be known to call Strasberg by his character name of Grandpa and once when asked about a contract by someone working on the film, Pacino started to assess it for him legally even though Pacino is an actor not a lawyer.
Actor Jeffrey Tambor had to wear a wig for several scenes. Scenes seen later in the film show him bald, and as scenes for movies are not usually shot in sequence, Tambor had shaved his head for the bald scenes, and so had to wear a wig.
The movie is notable for one particular scene which sees a justice, Judge Francis Rayford (played Jack Warden), firing a pistol in court. According to director Norman Jewison's audio-commentary, this was allegedly based on a judge in Texas who had unbelievably taken a gun to court. In one American borough, Jewison cited research that showed that five out of six criminal justice judges wore firearms.
When Jack Warden is seen sitting on the ledge of the law building four stories up, he really was. Warden was though wearing a security cable harness under his clothes as a safety precaution in case he slipped.
According to director Norman Jewison's audio-commentary, in legal circles the film was criticized for its portrayal and depiction of legal eagles, lawyers and judges. Jewison described the film as "a terrifying comedy".
One of the first major Hollywood movies of the modern era to shoot exclusively in Baltimore, Maryland. Most of the picture was shot on location there but some sets were built for filming on sound stages in the studio in Los Angeles. The majority of the film's casting was cast in New York though none of the picture was shot there.
The title is the last four words of the Pledge of Allegiance recited daily by US schoolchildren. Its full version reads: "I pledge allegiance to the flag of the United States of America, and to the republic for which it stands, one nation under God, indivisible, with liberty and justice for all".
Scenes showing courtrooms and the interior of the courthouse were filmed in the interior of Baltimore's Circuit Court building on Calvert Street, but exterior shots of the courthouse are actually of the War Memorial Building on Gay Street.