"Unbroken" is based on the true story of Louis Zamperini, a former Olympic athlete who survived a plane crash during WWII and was sent to a Japanese prisoner-of-war camp. Although the real Louis Zamperini was an adviser for the film, he doesn't have a role. He's played by Jack O'Connell.
Unfortunately, Louis Zamperini died before the film depicting his life story premiered. Thanks to director Angelina Jolie, though, he was able to watch a rough cut of the film in the hospital before he passed away. Notably, Louis Zamperini's real-life grandson Clay Zamperini makes a cameo in the film as an Olympic torch bearer.