Bing Crosby's performance is not a performance there really can be said all that much about. He sings well I guess as he usually does but that is not an acting performance. He mostly just looks and smiles in this performance. Even when he tries to change someone's mind about something he just tells them smiling in his usual way. There really is not all that much to his performance and O'Malley's character is rather strange in this film actually. For example he really undercuts the Sisters for no reason many times, and why exactly did he praise the bully for beating up the kid exactly. O'Malley is rather odd with his imperfectness in this one that does not work, and I think the just about perfect guy in Going My Way works much better.
Crosby actually stays in the background a lot of the time, and the little good cheer that is in the film is mostly brought by Ingrid Bergman as the Mother Superior Sister Benedict. Her performance is not anything amazing but it really shows how little Crosby does in his entire performance. He just smiles, or sings that is it, except perhaps his final goodbye to Sister Benedict at the very end of the film. He actually has some emotion in that scene rather than just relaxed happiness of the rest of his performance. That one scene, well not even a scene more of a moment is not much but at least it is something, unlike the rest of his performance, that really is the sleepwalking style of performance.
