Initially, the famous concluding catchphrase, "Good Night and Good Luck", that became the title of the film, was a habit Edward R. Murrow kept from his London years as a war reporter for the radio, when British people under constant night German bombing systematically ended their conversations with the very same words, uncertain to meet again.
During the DVD commentary for this film, George Clooney says that about twenty percent of the test audiences had never heard of Joseph McCarthy before and wanted to know the identity of the "actor" playing him. McCarthy, of course, was played by actual footage of the real McCarthy: Joseph Raymond McCarthy (1908-1957), who was the Republican Junior Senator from Wisconsin from 1947 to 1957, when he died in office.
Each morning, George Clooney would gather his cast members together, and give them copies of the newspapers from that day in 1953. He'd then give them an hour and a half, working on old manual typewriters, copying out the stories from the paper. He would then hold an improvised news conference with hidden cameras, in which the cast members would then pitch their stories to the editor, just like a real newsroom.
Joseph McCarthy's influence was already waning when Murrow's show about him aired, due to years of investigative reporting by other journalists, such as Drew Pearson. Edward R. Murrow himself said in Newsweek magazine, "It's a sad state of affairs when people think I was courageous" in presenting his show.
The band playing throughout the movie is Matt Catingub's band, and Matt Catingub did all the arrangements. Matt Catingub produced Rosemary Clooney's last album, and George Clooney (Rosemary's nephew) was so impressed, he personally asked Matt to do the music for this film.
The entire set was built on one floor. The elevator interior was built on a turntable, so it could be rotated to a new "floor" during unbroken shots. (In one scene, the CBS Records office is represented by a false wall that was then raised out of shot while the door was closed.)
Most of the text of Edward R. Murrow's speech bookending the movie is taken word-for-word from the actual keynote address he delivered to the 1958 RTNDA convention. The actual conclusion to the speech, after Murrow's line about television, used strictly for entertainment rather than education, being nothing more than wires and lights in a box, went as follows: "There is a great and perhaps decisive battle to be fought against ignorance, intolerance, and indifference. This weapon of television could be useful. Stonewall Jackson, who knew something about the use of weapons, is reported to have said, 'When war comes, you must draw the sword and throw away the scabbard.' The trouble with television, is that it is rusting in the scabbard during a battle for survival."
The man introducing Edward R. Murrow's keynote address to the 1958 convention of the Radio-Television News Directors Association cites Murrow's reporting on, among other topics, the plight of migrant workers. In fact, Murrow did not report on the conditions of migrant workers until 1960. His documentary on the subject, CBS Reports: Harvest of Shame (1960), was the last project he worked on as a CBS broadcaster.
The trivia items below may give away important plot points.
When William Paley (Frank Langella) meets with Edward R. Murrow (David Strathairn) and Fred Friendly (George Clooney) in his office to tell them that he is moving their show to Sunday afternoons, he replies to one of Murrow's objections with the line: "You should teach journalism, you and Mr. Friendly." In fact, years after leaving CBS, Friendly would go on to teach journalism at Columbia University.
In the film, Joe and Shirley Wershba's (Patricia Clarkson's) secret marriage is found out, and Joe voluntarily quits to avoid being fired. Joe Wershba (Robert Downey, Jr.) would spend six years writing for the New York Post, before returning to CBS, when their policies had changed, and would go on to be one of the original producers for another hit news show, 60 Minutes (1968).