Goofs

Dean O'Gorman (playing Kirk Douglas) had Douglas' signature cleft chin in his subsequent scenes but in his first scene with Trumbo, he didn't have a cleft.

At the picnic at Trumbo's house, Edward is sitting at the picnic table, looking at Dalton over his right shoulder. He asks Dalton a question, then Dalton is seen giving a short answer from the barbecue. When Edward responds, he is on the other side of the table, looking over his left shoulder.

When Nikola enters the living room, about 30 minutes into movie, Trumbo is laying on the couch, going through the script, holding a whiskey glass on his chest and smoking a cigarette. Camera only jumps to Nikola as she says "I thought you weren't allowed to write anymore..". As soon as camera returns to Trumbo, the glass is on the table and he's now holding the cigarette which is obviously way too consumed than it was before.

In the bathtub, the bottle of pills appears and then disappears.

During the opening credits, the copyright year is the Roman number MCMXI, which is 1911. It should have been MMXV, for 2015.

The Academy is shown presenting an award for "Best Original Story" for The Brave One (1956) to Jesse Lasky Jr. on behalf of the fictitious "Robert Rich". Though Dalton Trumbo, using the name "Robert Rich", wrote the screenplay for "The Brave One", he did not write its original story. The story had been written back in 1942 under the title "My Friend Bonito" by documentary filmmaker Robert J. Flaherty for Orson Welles' never-finished compilation film It's All True (1943).

Trumbo and former Congressman J. Parnell Thomas are shown in the same prison, but they never were. Thomas was imprisoned in the Danbury CT Prison with Lester Cole and Ring Lardner Jr., both members of the "Hollywood Ten". Trumbo served eleven months in the federal penitentiary in Ashland, Kentucky, not in Connecticut.

When Trumbo and his family go to see Roman Holiday (1953) in their local cinema, a caption gives the date as "January, 1953". The film didn't open in America until September of that year.

Hedda Hopper is asked how her son is doing in the Navy. She replies that he is a First Lieutenant.

While this is usually regarded as an Army rank, the title First Lieutenant also is given to the leading officer of the deck division on any U. S. ship.

Cleo Trumbo uses her 35mm film camera to take an indoor photograph of her daughter Niki Trumbo for her 16th birthday. At the time, no cameras were able to take a clear picture indoor without an additional light source. Actually, such indoor use of this camera type was common at least a decade before the period of the film.

When Trumbo is giving the final speech, the net holding the fake sideburns and the hair at the sides of the forehead is very visible.

Dalton Trumbo's mustache is solid in some scenes and has a space in the cleft above his lip in others.

When the Oscar is presented for Best Screenplay at the 1954 Awards the presenter says, "And the Oscar goes to..." This phrase was not used by presenters until the 61st Academy Awards in 1989. In the 1950s the presenter would have said, "And the winner is..." when presenting an Oscar.

In the final scene, Dalton Trumbo is shown giving his "only victims" speech before the Writers Guild of America. In 1970, when Trumbo gave the speech, it was still known as the Screen Writers Guild.

At 8:20 into the movie Trumbo references the drink thrown at him as "coke" which is a name not used in the 1940's for Coca Cola.

Two weeks before Christmas 1959, when Otto Preminger walks into Dalton Trumbo's home, he is seen carrying a full copy of the new script for SPARTACUS, the cover page at the bottom incorrectly says Universal City Studios, Inc., including the trademark. More than four years before Universal City Studios was created. Spartacus (1960) was released in the USA by Universal-International (Universal Pictures), with its World Premiere on 22nd September 1960 at the DeMille Theatre in New York, and on general USA cinema release from 6th October 1960. The long-awaited takeover of Universal Pictures by MCA, Inc. happened in mid-1962 as part of the MCA-Decca Records merger, and then in 1964 MCA Inc. formed Universal City Studios, Inc. from the merger of both Universal Pictures and Revue Productions.

When Trumbo and others leave the courtroom following their conviction for Contempt of Congress in the late 1940s, they're surrounded by reporters, many of whom are using microphones not introduced until the 1970s.