Prior to the movie, Renate Reinsve was ready to give up on acting to pursue a career in carpentry (Reinsve had then recently renovated a home and fell in love with woodwork). Just one day after making the life-changing decision to quit acting, Norwegian director Joachim Trier surprised her with an impromptu meeting, and together they mused about life and love, among other things. The last time the pair had worked together was over a decade ago, in Oslo, 31 août (2011), where Reinsve only had one line in an insignificant scene. Using their earlier conversation as a basis, Trier subsequently worked on the script for Julie (en 12 chapitres) (2021), with the intention that Reinsve would play the lead in it.
Joachim Trier's statement for the film: "For a long time I have wanted to make a film about love. One that goes a bit deeper than normal onscreen love stories, where everything is so simple, the stories so clear-cut, the feelings so admirably unambiguous. A film that will look seriously at the difficulties of meeting someone when you're struggling to figure out your own life; at how irresolute and uncertain even the most rational and otherwise self-confident people can become when they fall in love; and how complicated it is, even for romantics, when they actually get what they have been dreaming about."
Anders Danielsen Lie told director Joachim Trier before filming started, "I want to do the best acting I've ever done." Trier revealed, "He's gotten better with his craft, and he's gotten even braver about exposing deeper emotions." Danielsen Lie worked closely with costar Renate Reinsve to tell his character's story through her eyes, as she's the lead character. He added, "There's an old-fashioned masculinity to [my character]. He feels that he belonged to a time that has passed and he is alienated by the fragmentation of culture in the digital world." Danielsen Lie ended up receiving the best reviews of his career after the film premiered at the Cannes film festival.
According to Joachim Trier, the film has been referred to as "the rom-com for people who hate rom-coms."
The final installment in Trier's Oslo trilogy.