The costumes of “Wild Horse Nine” are as loud and colorful as the personalities wearing them. From the film’s outset, CIA buddy duo—the rambunctious Chris (John Malkovich) and his cantankerous, moustached companion Lee (Sam Rockwell)—do a bad job of blending in as they take on a joint-assignment to overthrow the Chilean government following the 1970 election of President Salvador Allende. Set against the rolling grass mounds of Easter Island, Chris and Lee meander around tourist resorts in vacation linens and fussy hats as they await instructions from their bureau chief back in Santiago. “We never know who [Chris and Lee] are. They are always playing a character,” the film’s costume designer Eimer Ní  Mhaoldomhnaigh tells The Set Set. To the general Chilean public, they are dressed to look like “just two guys” on vacation. 

Despite being undercover for the entirety of the film, Lee and Chris’ personal styles shine through their disguises. “I didn't want to present [Chris] as the guy in the suit in the office,” Mhaoldomhnaigh says. Rather, Chris wears statement button downs and suspenders. The duo’s eccentricity most clearly manifests in their respective hats. According to Mhaoldomhnaigh, “you can't have a cowboy without a cowboy hat,” so Lee naturally wears one alongside his subtly Western get-up. Chris’ hat, meanwhile, is a dated felt pork pie style. “John loved the hat and he kept the same style of hat [across settings],” Mhaoldomhnaigh says. When he arrives on Easter Island, Chris replaces it with a straw option, which Mhaoldomhnaigh and Malkovich agreed was more vacation-appropriate. The headwear dually-functioned as a prop, allowing Rockwell and Malkovich to lean into the physicality of their characters. “I always want to give [actors] something that they can work with, that they feel comfortable in, that when they come in in the morning and put on their costume, they can leave John and Sam in the dressing room until it's time to go home that evening,” Mhaoldomhnaigh explains. 

Drawing from the 1970s costume research she did for 2005’s “Breakfast on Pluto,” a ’70s-set comedy, Mhaoldomhnaig supplemented her preexisting notions of the period with photography books. “Online is a great resource but sometimes you're just seeing the same stuff over and over again,” Mhaoldomhnaig says when describing her preference for physical media. Mhaoldomhnaigh treated Easter Island like it was the film’s third main character. Growing up in Ireland and having previously worked on McDonagh’s “The Banshees of Inisherin,” the costume designer is no stranger to working with vibrant, verdant backdrops. “I knew that the ’70s colour palette was going to work with all those oranges and terracottas,” she says. “And I used a bit of green on [Lee] as well because I love playing with tone on tone.”

As the older and wiser of the duo, Chris sticks to older silhouettes like a 1960s suit from London that Malkovich immediately took a liking to during fittings. The character is sick throughout the film, as reflected by his perpetual cough and the slightly oversized fit of his  suits. Lee’s style inspiration came from classic American westerns, which Mhaoldomhnaig knew McDonagh’s was a fan of when pitching the cowboy schtick as a starting point for his costume. The get-up required a custom built cowboy hat and navajo silver accessories, like a turquoise encrusted belt buckle. Rockwell was one of the few ensemble actors who wore authentic ’70s vintage as well, sporting a few pre-loved knitted polo tops. 

When Lee and Chris run into two young Chilean students at the airport, Monica (Mariana di Girolamo) and Alicia (Ailín Salas), their youthful and modern “hippie boho chic” style juxtaposes against the men’s stiff, American wardrobe. Naturally, the girls' outfits become more leisurely once they are on Easter Island. When Lee runs into Monica on the beach, she wears a dress made out of floral yellow fabric with a vibrant blue head scarf, all handmade by Mhaoldomhnaigh’s team. The designer was “looking to really pare down what [Monica was] wearing, so we kind of see another kind of side to her where she’s not dressing up [and] trying to be cool with her friend.”

Lee’s wife, Marge (Parker Posey), only had two outfits throughout the film, both of which provide all of the characterization needed to understand her character. She is introduced in a silky, light brown leopard jumpsuit. Posey plays a different sort of “Party Girl” than her role in the 1995 comedy, the bored and neglected housewife, rather than the twenty-something club rat. “Because the characters are larger than life the worlds they inhabit can be exaggerated also and a little bit larger than life,” Mhaoldomhnaig says. Marge’s outfit was designed to look out of place in her domestic setting. “It's the middle of the day, she's got a drink in her hand and she's smoking, and you're thinking. Has she just come home? Is that her party outfit?” Mhaoldomhnaigh says. 

Marge’s second look finds her in a state of panic after the CIA pays a surprise visit to her home. Her sexy animal print is switched out for a tight-fitting blouse and trousers.“There's that sense of fear and paranoia, but it's still very sexy,” Mhaoldomhnaigh says, fitting Posey in a beige floral button up, adorned with coral accent flowers, and red highwaisted trousers, Alongside the other women’s wardrobe in the film, Mhaoldomhnaig custom built all of Posey’s wardrobe, starting with fabric swatches. The effect mirrored the hand-made quality of many real garments from the period, which were handmade from simple sewing patterns and loud fabrics.