Myrtle Mae Simmons - Teenage girl whose debut in society circles is upstaged by the arrival of her uncle Elwood and his invisible friend Harvey. But at least once Elwood is committed to the sanitarium, he won't be able to embarrass her any more...
Veta Louise Simmons - Sympathetic to her brother, but protective of her daughter, Veta reluctantly decides that the best thing to do is to commit Elwood. Of course, she's seen Harvey too, and we all know that that's crazy...
Elwood P. Dowd - Sweet, gentle, and the town tippler, Elwood nonetheless always seems to get his way. Perhaps he is protected from life's hardships by his invisible pooka...
Mrs. Ethel Chauvenet - Elderly dowager who comes to the tea reception just to see her favorite nephew Elwood. Needless to say, Harvey is quite a surprise to her. This is a smaller part, which could be combined with Mrs. Chumley.
Ruth Kelly, R.N. - Pretty young thing, she likes Elwood, but loves Dr. Sanderson.
Duane Wilson - The sanitarium hired goon. He hauls Veta off to the hydropool room, and then later tries to woo Myrtle Mae, as only he can.
Lyman Sanderson, M.D. - Brilliant young doctor, with the minor exception that he commits the wrong person to the sanitarium. Smitten with Nurse Kelly.
William R. Chumley, M.D. - Brilliant older doctor who runs a nice quiet little sanitarium until Elwood shows up. And then he sees Harvey.
Betty Chumley - The doctor's wife, who has a nice chat with Elwood while waiting for her husband to take her to a cocktail party. This is a smaller part, which could be combined with Mrs. Chauvenet.
Judge Omar Gaffney - Shrewd old man, a friend of both Elwood and Veta, he just wants to get the facts straight and to settle this Harvey business.
E. J. Lofgren - Cab driver whose imperative need for $2.75 sends the play spinning to its denoument. A nice cameo part.