Harvey is a charming, weird movie. It's weird because of how the movie takes on its premise, and actually treats it as a kind of serious comedy, or a very light-hearted drama. The factor I think is the mental hospital, where-in his sister wants to commit him (played by Oscar-winning Josephine Hull, mostly in a performance where she has to cry a good deal and be in hysterics). But, needless to say, due to a misunderstanding he commits *her* instead (and maybe latent sexism perhaps, that this male doctor doesn't trust this woman, but I digress), and Elwood walks out. Now the doctors and everyone gave to get him back. But will it be such a struggle to get him there?
Stewart is the reason to see this movie, as is the case with all of his major performances and this is certainly one of them. As Dowd he commands the screen and yet is so genial and friendly to all of the characters. The movie is ultimately a comedy of manners as much (if not more) than about some crazy person. The writing, based on a play, takes the time to understand this man, and by proxy Stewart fully understands him, and really admires him it seems like. We kind of want to believe this rabbit exists (maybe, and this isn't a spoiler so much as a hint, maybe it does?) by how Elwood makes it seem... alright, somehow. What do you do with someone who isn't seeing things as 'normal', but has the sort of good manners and respect for others, even those who may not deserve it, that would give regal families a run for their money? Stewart gives Elwood charm and humility and, at one point, kind of a tragedy when he tells about what it is he does to the doctor and his assistant in the alley (that may be the best scene in the film).
It may not be a perfect movie; the supporting performances are a mixed bag for me, or it may also be in the writing. As the characters scramble and get into misunderstandings and even a possible romance (!) blooms between one of the orderlies and Elwood's niece, it's a lot of like comic stuff that only adds so much to the narrative. And yet it's hard to begrudge these creations - and Hull, though sort of one note, gives Veta Simmons her all - because Elwood strips down their devices through so much kindness and warmth. If anything Harvey is so strange because it isn't afraid to be so genuine in spirit, and it's disarming at first (and the laughs are bigger, and sporadically it's a very funny time) and then one comes to see it's just how the movie is. And of course it's the right move to make the rabbit an invisible thing; the moment it's actually *there* on screen, the magic is lost.