On October 22, 2012, it was announced that Shailene Woodley had landed the lead role of Beatrice “Tris” Prior. Lucas Till,Jack Reynor, Jeremy Irvine, Alex Pettyfer, Brenton Thwaites, Alexander Ludwig and Luke Bracey were all considered for the role of Tobias “Four” Eaton. On March 15, 2013, it was announced that Theo James had been cast as Four.
Though James was 10 years older than the character when cast, Roth praised his casting “I was sure within seconds: this was ‘Four’, no question. Theo is able to capture ‘Four’s’ authority and strength, as well as his depth and sensitivity.” She also mentions the chemistry between him and Shailene: “He is a perfect match for Shailene’s incredibly strong presence as Tris. I’m thrilled!” The producers said about his casting: “We took our time to find the right actor to fill the role of Four, and Theo is definitely the perfect fit. Veronica has crafted a truly iconic character in Four and we cannot wait to begin production and bring him and this story to life for millions of fans around the world.”