Supporting actors include William Jackson Harper, Vilhelm Blomgren, Ellora Torchia, Archie Madekwe, and Will Poulter.

A co-production between the United States and Sweden, Midsommar was initially pitched to Aster as a straightforward slasher film set among Swedish cultists.

While elements of the original concept remain in the final product, the finished film focuses on a deteriorating relationship inspired by a difficult breakup experienced by Aster himself.

The film's soundtrack, composed by the British electronic musician Bobby Krlic, takes inspiration from Nordic folk music.

The film grossed $48 million and received positive reviews, with praise for Aster's direction and Pugh's performance, although its violent content polarized general audiences.

In the middle of winter, an American student, Dani, is traumatized after her mentally ill sister Terri kills their parents and herself via carbon monoxide poisoning.

The commune elder, Siv, attempts to calm Connie and Simon by explaining that every member does this at the age of 72, which is considered a great honor.

He discovers Josh's severed leg planted in a flowerbed and a barely alive Simon on display in a barn, having been made into a blood eagle.

[7] According to Aster, he had been approached by B-Reel executives Martin Karlqvist and Patrik Andersson[8] to helm a slasher film set in Sweden, an idea which he initially rejected as he felt he "had no way into the story."

Aster ultimately devised a plot in which the two central characters are experiencing relationship tensions verging on a breakup, and wrote the surrounding screenplay around this theme.

"[9] Aster has mentioned 1981 Albert Brooks film Modern Romance as an inspiration for Midsommar, and also called it "The Wizard of Oz for perverts".

[11][12] He researched Hälsingegårds, "centuries-old farms that typically had painting on the walls", to develop a stylized version for the set, as well as May Day and midsummer celebrations in Swedish, German and English folklore.

[12] Florence Pugh, Jack Reynor, Will Poulter, Vilhem Blomgren, William Jackson Harper, Ellora Torchia, and Archie Madekwe joined the cast in July 2018.

[16][17] Pugh reflected "the shoot was totally nuts" and commended Aster's direction: "he was dealing with possibly 100, 120 people, additional extras and actors there, all speaking in three different languages and he was the captain of the ship".

[17] Reynor said he spent time attempting to boost morale among the extras involved, none of whom spoke English, and Isabelle Grill (who plays Maja) who was appearing in her first feature film role.

[8] Svensson said the mallet prop used for the senicide scene was a replica of one at a museum in Stockholm, and that the cliff-jumping was based on historic practices in Sweden.

[8] In April 2020, A24 announced it would be auctioning off props from its films and television series, including the 10,000-silk-flower May Queen dress worn by Pugh, which was reportedly purchased by the Academy Museum of Motion Pictures for $65,000, after both Ariana Grande and Halsey had expressed interest on social media.

However, he attributed its uneven audience reception to negative aspects, such its length, its lack of subtlety, its derivativeness and poor use of genre clichés, its over-stylization, its tendency to be over-serious, the implausible plot, the one-dimensionality of the characters, which Birrell found irritating, and the fact that he did not find the film scary.

The site's critical consensus reads, "Ambitious, impressively crafted, and above all unsettling, Midsommar further proves writer-director Ari Aster is a horror auteur to be reckoned with.

[48] John DeFore of The Hollywood Reporter described the film as the "horror equivalent of a destination wedding", and "more unsettling than frightening, [but] still a trip worth taking.

"[50] David Edelstein of Vulture praised Pugh's performance as "amazingly vivid" and noted that Aster "paces Midsommar more like an opera (Wagner, not Puccini) than a scare picture," but concluded that the film "doesn't jell because its impulses are so bifurcated.

"[9] In The New York Times, Manohla Dargis was critical of the character depth behind Dani and Christian, finding them "instructively uninteresting" and stereotypically gendered as a couple.

[51] Eric Kohn of IndieWire summarized the film as a "perverse breakup movie," adding that "Aster doesn't always sink the biggest surprises, but he excels at twisting the knife.

"[52] Time Out's Joshua Rothkopf awarded the film a 5/5 star-rating, writing, "A savage yet evolved slice of Swedish folk-horror, Ari Aster's hallucinatory follow-up to Hereditary proves him a horror director with no peer.

[54] Writing for Inverse, Eric Francisco commented that the film feels "like a victory lap after Hereditary", and that Aster "takes his sweet time to lull viewers into his clutches ...

[57] Tomris Laffly of RogerEbert.com rated the film 4 out of 4 stars, describing it as a "terrifically juicy, apocalyptic cinematic sacrament that dances around a fruitless relationship in dizzying circles".

Rose proposes that the film may be read as a "parable of snarky, city-smart, modern rationalism undone by primal rural values".

"[12] Monica Wolfe, a PhD student, asserted in the Journal of Popular Film and Television that Midsommar reflected themes of globalization and American imperialism.

[69] Yusuke Narita, a Japanese professor at Yale University, positively cited a scene in the film where an elderly person is forced to jump off a cliff.