Liev Schreiber accepted the role of the film's main antagonist, the Storm King, because he was eager to appear in a film he would be able to take his children to see, noting his repertoire of violent, adult-oriented films.
At PonyCon AU in Australia, it was stated that the film would not be related to Equestria Girls and that the production staff is "going all out on it, to make sure it doesn't just feel like an extended episode."
Describing what the movie's scope was like, Tara Strong, voice actress for Twilight Sparkle, stated in an interview, "Working on the feature was similar to working on the show, just that the stakes are higher and the adventure is bigger. We leave Equestria and find out that there are other lands. There's something that forces Twilight to have to rely on her friends to help set things right. Any time you go from a series to a feature, you have to have a big story, and they certainly accomplished that."
Michael Peña ad-libbed much of the character's dialogue, with Meghan McCarthy saying, "You get Michael Peña in a recording booth, and you just are like, 'Please just go and say funny things.' He will be there for hours, just giving you all kinds of really great material that was not something that we had originally scripted!"
On the development of the character, screenwriter Meghan McCarthy said, "We just arrived at this idea of a character who had come from Equestria, and had not had the positive experience that Twilight [Sparkle] and her friends had. It felt like a good counterpart to our heroes was to have a villain who didn't just not get friendship, but had a reason that she didn't understand it."
While the initial returns were considered poor from some sites, Cartoon Brew's Amidi stated that since Lionsgate is not directly in the business of releasing family-friendly films, the opening take readily exceeded the distributor's other attempts at this genre; likewise, Amidi estimated that the film had a budget between $5 to $8 million, based on budgets for films with similar styles as well as accounting for the work being done primarily in-house at Hasbro to reduce costs.
Muffins (Derpy) speaks for the first time since the 100th episode of the series, yelling Twilight's name right before she sacrifices her self to save the Princess and than later when gasping for air after being freed of her crystal state.