The original heartthrob
Ethan is, in part, based on a real-life person. What I like to say is that present-day Ethan is very much a fictional character, but young Ethan, the Ethan we learn about through memories and stories, was heavily influenced by someone I know. And that someone had James Dean hair.
It's probably Ethan's most defining physical feature and it's described several times in the book. When Kate meets Ethan, it's the first thing she notices about him.
It was hard to make out the details of his face in the dim light of the alley, and difficult to discern his age, but I could see the outline of his unruly, wavy hair twisting up every which way.
I printed this image of James Dean and pinned it to my wall for inspiration. It's been so influential to me in creating Ethan's character because it captures so much of the essence of what Ethan's about - not just the hair, but what it stands for: attitude, darkness, hidden romance. It's an image any girl, good or bad, would remember and tuck into the pages of her journal for safekeeping. It's a face you can't forget.