After a screening of the film in Kansas City, Kevin Smith interviewed two life long Westboro Baptist Church members (Shirley Phelps niece and son) who had defected a few years prior. They both enjoyed the film and even complimented Smith on how realistic certain aspects of religious fanaticism are depicted.
The Westboro Baptist Church planned to protest Red State at its premier at the Sundance Film Festival. Kevin Smith in turn planned a counter protest which he and his fans took part in. At the premiere the counter-protesters heavily outweighed the handful of Westboro protesters who showed up. This occurred 12 years after Smith's first film to tackle religious controversy, Dogma (1999), drew protests from certain sects of the Catholic Church, one of which Smith jokingly took part in himself.
Shot over a period of 25 days, using the all-digital Red camera system, director and editor Kevin Smith could edit the footage the day he shot it. Because of this between shooting scenes Smith would be editing almost non-stop. As a result, a mere 2 days after the last shot was done, Smith was able to show a fine-cut of the film to the entire cast and crew at the wrap party.
Kevin Smith wrote the role of Abin Cooper for Michael Parks after seeing his performance in From Dusk Till Dawn (1996). Smith has said that if Parks had not agreed to be in the film, he would have dropped the project entirely.
At the premier of the film at the Sundance film festival, Kevin Smith said he would "pick the distributor 'auction style'" immediately following the screening. After the screening he then pulled producer John Gordon on stage to conduct the auction. Smith then bid $20 for distribution rights and Gordon immediately sold it to him. Smith revealed it was his plan all along to self-distribute the film himself.
Released on tour in March 2011, Kevin Smith invited the WBC and specifically Megan Phelps-Roper over Twitter to attend the Kansas City screening and Q&A. Megan and around 15 other members of WBC attended the screening and some brought their young children along. Smith warned the family that the film's content was for a mature audience and not suitable for children, but was promptly told off by the church members. Less than 20 minutes into the screening, the entire WBC audience attending the event walked out, outraged by the film's content. Megan called the film "filth" and "a vulgar piece of tacky melodrama."
Little did Kevin Smith know Michael Parks was actually a country singer early in his career who sang with the likes of Johnny Cash. Many of the country-gospel songs sung in the film were suggested by Parks during filming. Later after the film was completed Parks re-recorded the songs onto an album.
Kevin Smith wrote the script around the same time he was writing Zack and Miri Make a Porno (2008) and presented them both to the Weinstein brothers. They immediately gave the green light to Zack and Miri Make a Porno, but declined on Red State fearing its story was too bleak to attract an audience. Had they green lit, Red State would've been shot back to back with Zack and Miri.
The megaphone John Goodman uses when announcing his team's arrival is actually from Kevin Smith's home where he would use it to communicate with his pets and family. Smith thought that it looked professional enough and that Goodman's character might pick it up on the way as "a sort of last minute, oh 'sh--t' sorta thing."
The trivia items below may give away important plot points.
In one of his Q&As, Kevin Smith revealed that the original ending to the film featured the Apocalypse: after Cooper taunts Keenan, he and the other members of the church along with every agent, save Keenan, dies with their hearts and heads exploding. After hiding during the violence, Keenan uncovers his eyes to see the last church member being killed by a gigantic angel, who sees Keenan and simply puts its fingers to its lips and goes "Shhhhh..." before ascending to Heaven as the Four Horsemen of the Apocalypse descend onto Earth.
In the sequence outside the compound when Agent Keenan (John Goodman) yells at Sheriff Wynan (Stephen Root) to go back into his car, Root's subsequent stumble and fall was unscripted. Root admitted that he was genuinely startled by Goodman's performance, and was happy to have Smith keep the footage in the film.
During filming Nicholas Braun suffered a concussion; when the CO2 squib fired, he fell back and the pressure from the squib knocked a box off a shelf and onto his head. According to Kevin Smith, when he showed up at the emergency room escorting Braun, the actor was still wearing a prosthetic gunshot wound on his forehead, sending the E.R. staff into a frenzy.
Due to the limited budget, a number of the smaller characters were played by family members and friends of cast and crew. One of the youngest believers was played by Ivy Klein, daughter of the film's cinematographer David Klein. Ivy was carefully prepped for the scene in which Cheyenne ('Kerry Bishe') tells the three young girls to go hide in the attic. However when it came time to shoot the scene, Ivy actually got scared and started screaming, which was not in the script. Smith got her parents' approval to use the footage in the movie. Smith felt terrible for scaring Ivy, and offered her father some money to take Ivy to a toy store. Her father replied, "Add it to the pile", as other cast/crew members had felt the same. According to Smith, the next time that Ivy saw Kerry was two days later at the Craft Services area. Ivy got a scared look on her face and said, "You're not going to act again are you?"
Smith originally planned to have the first "prisoner" executed with a goat's head on top of his own. The special effects director told him that he might be thinking of a ram's head, because a goat is actually very small. Smith found out shortly thereafter that the ram's head would cost $5,000 - his entire special effects budget - and scrapped the entire idea. He came up with the plastic wrap and top-down shot because he thought it would contain the most "blood" and therefore not require much cleanup between takes.
Smith has said that there are ten "Easter Eggs" (hidden jokes or surprises) in the film. He plans to only discuss each one as they are discovered by fans. The first is that Sheriff Wynan "enters and exits the film with a shot to the face."