Jonathan Safran Foer's inspiration for his main character came when having difficulty with another project. In an interview, Foer stated, "I was working on another story and I just started to feel the drag of it. And so, as a side project, I got interested in the voice of this kid. I thought maybe it could be a story; maybe it would be nothing. I found myself spending more and more time on it and wanting to work on that". On the challenges of writing a novel in a child's voice, Foer responded, "It's not the voice of a child exactly," adding that "in order to create this thing that feels most real, it's usually not by actually giving the most accurate presentation of it."
Foer combined the character he had been developing with the 9/11-centered plot. He created the story line from his personal experiences and reactions regarding the terrorist attacks on 9/11. Foer was sleeping off jet lag after returning to New York City from a trip to Spain, when he was woken by a phone call from a friend: "He said, 'You have to turn on the TV, a plane has crashed into the World Trade Center.' And then he said, 'I think it's going to be a very strange day.'" In another interview, Foer said, "I think it's a greater risk not to write about [9/11]. If you're in my position—a New Yorker who felt the event very deeply and a writer who wants to write about things he feels deeply about—I think it's risky to avoid what's right in front of you."