Actor-Shared Background: Neal McDonough was not only from an Irish family who migrated to America, but he was also born in Boston, Massachusetts; just like Dum Dum Dugan himself!
The biggest reason why Stanley Tucci took the role of Abraham Erskine was because he'd never had a role that required a German accent, and he wanted to try his out.
Hugo Weaving:"It was fun to play; I enjoyed the outrageousness of the German accent that I employed and I enjoyed the extraordinary mask and costume, even though it was unbelievably hot inside it. I enjoy mask work; I enjoy trying to animate masks and reveal certain things that the mask itself might not reveal. V for Vendetta was another example of that, but there was less animation within that mask versus the Red Skull. With Marvel, it's pretty basic stuff: accept the deal and enjoy the ride. It’s not a major stretch for an actor, but on the other hand the difficulty with the Marvel universe is maintaining a link to a human dimension within such an extraordinary, technological CGI universe. In terms of me going back and doing another one, I don't know. I'm not sure what they're up to with the Red Skull."
Dyeing for Your Art: Chris Evans got ripped, and waxed his body, for the role and dyed his hair golden blonde (he's a natural brunette).
Enforced Method Acting: Hayley Atwell had not seen Chris Evans' body before shooting the scene where Steve comes out of the testing chamber, meaning her flustered reaction to his muscular physique was quite genuine.
Englishman Dominic Cooper as Howard Stark, American playboy and captain of industry.
English Natalie Dormer as the American soldier who kisses the Captain. Although, amusingly, her only scene is set in England.
English Jenna Coleman as one of the girls Steve and Bucky go on a double date with.
English Lex Shrapnel as the American soldier Gilmore Hodge.
English Laura Haddock as Captain America fangirl, who is most likely an American. Later retconned to be Peter Quill's maternal grandmother, who is definitely an American.
Irony as She Is Cast: Steve mentions he's not much of a dancer but Chris Evans trained in ballet and credits it for developing his strong core and allowing him to take on such a physical role.
Market-Based Title: Some markets simply called the film First Avenger out of fears that anti-American sentiment might keep audiences away if they kept "Captain America" in the title.
Money, Dear Boy: Hugo Weaving has gone on record stating that he is indifferent to the film and has very little interest in reprising his role as the Red Skull, due to the difficulty of the makeup process involved. Even though his attitude towards it has changed, Weaving declined to come back for Avengers: Infinity War and Avengers: Endgame due to monetary concerns.
The Other Darrin: Howard Stark was portrayed by Gerard Sanders in still photos, John Slattery in archive footage and Dominic Cooper in life. Justified as all three depictions are from different time periods — the still photos are from around Tony Stark's pre-teens and beyond, the archive footage from his childhood, and in real life it's the '40s long before he's even born, so Howard ages significantly between each depiction. Slattery and Cooper have continued to portray the character in subsequent MCU works depending on what the time period depicted is.
Cap's early career mirrors how Captain America started as a propaganda piece, and early issues of the comic are made in-universe to help this. In fact, Golden Age comics like Captain America were used to promote and sell war bonds. Hence the Superman cover asking readers to buy one to "slap a Jap."
His poor reception with the troops is the same as several 1940s actors who got out of the draft because they were making morale-raising war movies.
Saved from Development Hell: The film languished in development hell as far back as 1997. In May 2000, Marvel teamed with Artisan Entertainment to help finance the film. However, a lawsuit arose between Marvel Comics and Joe Simon over the ownership of Captain America copyrights, disrupting the development process of the film. The lawsuit was eventually settled in September 2003. The rights were later acquired by Marvel in 2005 who were planning to independently produce several films with Paramount Pictures distributing, and the film finally saw release on July 22, 2011.
Scully Box: For some scenes, Chris Evans knelt down on boxes to get the height and eyeline correct for pre-serum Steve.
Jeff Goldblum was approached for a cameo as the senator who gets Steve involved in the USO, but it didn't work out. Goldblum would eventually portray the Grandmaster in Thor: Ragnarok.
Jeremy Strong was considered to be the body double for Steve Rogers' pre-serum body at one point. Despite Strong and Chris Evans having grown up in Massachusetts together, he ultimately passed on the role due to being overly dissatisfied with Hollywood acting.
Scarlett Johansson was rumored to appear as Natasha Romanoff. It would have been most likely that her role would have been Amanda Righetti's role as the S.H.I.E.L.D. Agent pretending to be Steve's nurse at the end of the movie.
Chris Evans turned down the offer to play Captain America several times; not out of dislike for the role, but because he feared what the effects of the sudden increase of fame would be on his private life. Then Robert Downey Jr. convinced him to take the part and thus gain the freedom to sign on any other role he'd want to after, and the rest is history.
Up until a very late stage in pre-production, HYDRA would have been a blatantly Nazi paramilitary organization, with swastikas on their uniform. The implication is still present in the final version, however, with Schmidt being portrayed with a swastika arm-band when threatening Erskine in a flashback. In addition, deleted scenes also had HYDRA explicitly attacking Nazis in addition to Allied powers.
Wolverine and Magneto were originally planned to have cameos (the former as a soldier and the latter in an internment camp), but it fell through due to copyright issues.
Captain America's shield initially had a very different design than in the final movie, but it was canned due to Stephen Broussard and Kevin Feige believing that it looked far too cartoonish.
This was the last Marvel Cinematic Universe film distributed fully by Paramount, though their logo was contractually obligated to appear on the first two MCU installments distributed by Disney, The Avengers and Iron Man 3. This was not Paramount's first involvement in the Captain America franchise. Since 1995, it has owned the US television rights to the 1990 film, a result of being acquired by Viacom, which had held the US TV rights to the library of production company The Cannon Group. Since 1999, it has owned the 1944 Republic Pictures serial, after Viacom acquired Spelling Entertainment Group. Paramount would only own distribution rights to The First Avenger for two years; in 2013, Paramount sold its distribution rights to the MCU films it had distributed to Disney.
.Hugo Weaving: "It was fun to play; I enjoyed the outrageousness of the German accent that I employed and I enjoyed the extraordinary mask and costume, even though it was unbelievably hot inside it. I enjoy mask work; I enjoy trying to animate masks and reveal certain things that the mask itself might not reveal. V for Vendetta was another example of that, but there was less animation within that mask versus the Red Skull. With Marvel, it's pretty basic stuff: accept the deal and enjoy the ride. It’s not a major stretch for an actor, but on the other hand the difficulty with the Marvel universe is maintaining a link to a human dimension within such an extraordinary, technological CGI universe. In terms of me going back and doing another one, I don't know. I'm not sure what they're up to with the Red Skull."