During the early stages of production, Bryan Cranston auditioned for the role of Jerry, and Gustavo Goulart (Brazilian actor and singer) was invited to perform Ethan's voice, but he was already committed to another project by that time.
Creators Dan Harmon and Justin Roiland have stated that they conceived a backstory for Rick with no intention of ever revealing it, because they are of the opinion that too many shows "jumped the shark" by revealing too much details. However, they have admitted to putting in clues to one of Rick's dark secrets since the beginning, and later confirmed that a fan had correctly guessed the secret in an on-line forum. By a process of elimination, fans have been able to narrow it down to four fan theories: Rick is aware that he is a fictional character; Rick's constant drinking isn't alcoholism, he is drinking an extract that keeps him super-intelligent; Rick is actually an aged Morty who traveled back in time; and finally: Rick's 'original Morty' is dead, and has been replaced by a copy from a parallel dimension.
Justin Roiland (co-creator of the show and the voice of Rick and Morty) said in an interview that Chris Parnell, who plays Jerry Smith, nails his lines on his first takes. However, because of normal voice recording precautions of animation, Parnell has to record at least thirty more takes. Even so, Roiland said that he almost always chooses Parnell's first takes.
Morty is generally accepted as being based on Marty from Back to the Future (1985). In "Close Rick-counters of the Rick Kind," one Rick has a Morty who looks like Eric Stoltz. Eric Stoltz was originally cast as Marty in Back to the Future (1985).
Alex Hirsch, the creator of the animation series Gravity Falls (2012), made a guest appearance on this show in the second season episode, "Big Trouble in Little Sanchez." He voiced a character called "Toby Matthews."
The main universe in the show's story line, "C-137", might be a reference to Cesium-137, a byproduct of nuclear fission and the most problematic environmental hazard after nuclear reactor accidents. In at least one episode Rick uses cesium against a powerful enemy.
Morty's voice is very reminiscent of Michael J. Fox's when he was younger and especially in Back to the Future. Rick and Morty was based on an original cartoon where Rick was "Doc" and Morty was "Mharti".
In the episode "Raising Gazorpazorp," the ruler Mar-Sha and the other Gazorpian with her are voiced by Claudia Black and Virginia Hey, respectively. Black and Hey also both played leading roles in the science fiction series Farscape (1999).
Unlike most animated shows, Rick and Morty's seasons aren't done simultaneously. Instead, the seasons are announced after they're finished and each season is usually separated by two years. This is unlike most shows whose seasons are separated by a few months.
Along with a rough version of Morty's caricature, a rough version of both Rick and Morty's voices can be heard in the second to last episode of "Mr. Sprinkles." Dan Harmon and Justin Roiland used the pseudonymous John Dreams and Larry Dune, respectively, for the two-minute eighth episode show. It was described by critics as "Heavy Handed."
A strange-looking helmet can be seen on Rick's work bench in many episodes. He can even be seen fiddling with the helmet at the beginning of the episode Vindicators 3: The Return of Worldender. The presence of said helmet has led to a dark new fan theory that is based around the urban legend of the suicide helmet, in which a troubled teenager builds a helmet rigged with shotgun shells that he uses to commit suicide. Rick's helmet contains several red tubes protruding from its surface that look unsettlingly like shotgun shells. Rick has had many close calls with death over the show's run, but given his unstable and often highly depressive mindset, it is believable yet very unfortunate that he would willingly build a device for such a purpose. Others have argued that the helmet looks a bit like the the brainwave-analyzing helmet worn by Doc Brown in Back to the Future (1985) as he tries to reads Marty's mind. Given that the show is based on Doc and Marty from Back to the Future, this theory isn't too far-fetched either (and the helmet seems to contain a set of goggles, which seems a bit unnecessary if its purpose is to kill the wearer).
On April 1st, 2018, Adult Swim aired a surprise Rick and Morty short called the Bushworld Adventures that has a much different take on the characters. The short was written and produced by youtuber Michael Cusack.
The trivia items below may give away important plot points.
It is suggested that this show takes place in the same universe (or multiverse) as Gravity Falls (2012), another popular cartoon, as items seen falling in a portal in the latter appear falling out in the former.
In Season 2, Episode 3, at about 18:44, the show that Unity created for Rick is revealed to be an alien version of Community (2009), a show which Dan Harmon created along with being the co-creator of Rick and Morty (2013), with all the characters from that show making an appearance in this show: Jeff, Annie, Shirley, Pierce, Troy, Abed, and Britta. Rick's requests from unity to "cancel it, then put it back on, then cancel it again" is also a reference for the ups and downs that the show had seen.
The viral outbreak that caused Cronenberg's outbreak in Season 1, Episode 6, titled "Rick Potion #9," is a reference to Canadian director David Cronenberg. The decision to use his name is likely due to the fact that Cronenberg is one of the originators of the "body horror" genre, a style of filmmaking which explores people's fears of bodily transformation and infection.
It is suggested that Rick & Morty and the show Futurama are set in the same universe as there have been many sightings of the Planet Express ship, from Futurama. For example, season 3, episode 1, and many more. There are also some sightings of the famous beverage Slurm.
In the episode 'Vindicators 3: The Return of World Endedr' (S3E4) the countdown to Rick's first Saw challenge ends on 0:42. 42 is the answer to life, the universe, and everything, in Douglas Adams cult classic book, A Hitchhikers guide to the Galaxy.