The premise of this series is partly based on the true story that broke in 2010 of a cell of Russian Sleeper agents who had been "hiding in plain sight" in the United States for decades. Several of them had had children, coworkers, friends, and neighbors who all had no idea that they were spies. These agents were ultimately returned to Russia in a trade for some Americans who were being held by Russia.
Joseph Weisberg created the show. Weisberg worked in the CIA's directorate of operations from 1990 to 1994. As a former agent, any script written by Weisberg must go in front of the CIA Publications Review Board.
In real life, Annet Mahendru speaks 6 languages (German, English, Russian, French, Persian and Hindi) due to a nomadic upbringing all across the globe. She joked that she was hired because the producers thought she was an actual spy.
The actors who play married couple Elizabeth and Philip Jennings on this show, Keri Russell and Matthew Rhys, also started dating in their real lives (in 2014). In January 2016, Us Weekly reported that Russell was four months pregnant with their first child together, and that summer, Russell gave birth to a son, Sam.
The season four episode "Clark's Place" contains the song "Under Pressure" by David Bowie and Freddie Mercury. The rights to the song were obtained from Bowie only two days before his death in February 2016, making this one of the very last clearances he granted in his lifetime; he allowed the filmmakers to use the song because he was a fan of the series.
Real-life Reagan staff member Oliver North, most famous for his role in the Iran-Contra affair, is a fan of the show. He has even helped consult on the historical accuracy, in particular the Contras' training camp arc in season 2 episodes "New Car" and "Martial Eagle."
Keri Russell was 7 months pregnant with her son Sam when she completed the fourth season of the series. The filmmakers got around this mainly by setting the season during the winter so she'd mostly be wearing heavy coats, as well as occasionally using CGI to remove her bump.
Noah Emmerich initially turned down the role of Stan because he was tired of playing law enforcement parts. It was his friend and the show's producer/pilot director Gavin O'Connor who convinced him to take a second look at the material.
On the wall of the inner office at Philip and Elizabeth's travel agency, there's a large poster advertising travel to Patagonia. Matthew Rhys starred in Patagonia (2010), speaking his native language, Welsh.
Slate Magazine's podcast about the show reported that during the later seasons, the Russian dialogue and other Russian text appearing on screen (on documents, props, etc.) has been translated from the screenwriters' English into Russian by Masha Gessen. This is a fun side-job for Gessen, whose highly regarded, award-winning, and very serious journalism on Russia has appeared in such publications as the New York Times, the New York Review of Books, the Washington Post, Granta, Slate, Vanity Fair, Harper's, and many others; she is also the author of several nonfiction books on Russian and Slavic history and current events. Gessen was born in Moscow and moved with her Russian-Jewish family to the United States when she was a teenager; she is also an activist against Russian persecution of the LGBT community.
During preparation of season 5 the KGB Colonel new-entry character Anatoli Victorovich was actually assigned to Louis Per Bruno, unavailable at that time due to bureaucratic matters which forced the network to replace him.
The trivia item below may give away important plot points.
During Season 3, when Paige finds out about her parents' real identities, one of her many questions for them is why they don't have accents, to which Philip starts to explain that they were very well-trained to lose them. This interchange is an inside nod to the fact that in his real life, Matthew Rhys (the actor who plays Philip) speaks English with a strong Welsh accent. Like Philip, Rhys's first language was not English; also like Phillip, Rhys is able to imitate an American accent nearly flawlessly due to his extensive training (though in Rhys's case, his training was as an actor, not a spy).