Jannings plays Professor Rath, a stogy Literature professor at a small college. We see his cleaning lady grouse about how his apartment is piled high with books and reeks of cigar smoke, and we realize that this is a man who leads a cloistered life.
One day in class, he confiscates a sexy postcard from his students, and finds out that some of them have been stealing out at night to see the girl on the postcard. That would be the nightclub singer Lola Lola (Dietrich). He finds himself in her dressing room and tries to berate her for corrupting his students, but she is breezy and carefree with him, and he is completely flummoxed. She takes off her nylons in front of him, and when she drops her panties down to him as she climbs the stairs, his goose is cooked.
Rath contrives to go back the following night, and this time decides that he has to rise to defend her honor against a drunken sailor. One criticism of this movie is that there really isn’t the feeling that she should care about this old man, but watch Lola in this scene as Rath forcibly throws the sailor out of her room. The camera goes to her, and you can see that she is touched by this gesture – That a man is defending her honor. The next thing we see is Rath waking up in her room after an apparent sexual encounter.
Rath’s colleagues at the college have heard about this by now, and his superior basically tells him that he can’t jeopardize his career by hanging around with a woman like that. Rath pulls himself up and says, "You are talking about my future wife." Soon the professor has quit his job, married Lola and moved in with the travelling revue with her. Rath goes through a physical transformation, as he grows slovenly and bitter in his new life. There is a terrific little montage of him testing the heat of a curling iron that indicates the passing of four years.
By this time, Rath is part of the show – He dresses like a clown and is the "appentice" of the magician Keipart. Finally the revue returns to Rath’s hometown, and he faces the prospect of going on stage in front of former colleagues and friends. To make matters worse, Lola is beginning an affair with a handsome strongman, and is doing so in plain view. So we come to the film’s climax – Rath goes onstage and is humiliated publicly – He is forced to crow like a rooster while Keipart cracks eggs on his head.
‘The Blue Angel" is notable on its’ own merits, but also because of the people involved. This was the first collaboration of Dietrich and director Josef Von Sternberg. They made seven movies together, including "The Scarlet Empress" and ""Shanghai Express". The partnership was such that it’s impossible to think of one without the other.
Then there is Emil Jannings, a textbook case of life imitating art. In many of his most famous roles, he played a man in a position of respect who is brought down. In addition to "The Blue Angel", there was his hotel doorman in Murnaus’ "The Last Laugh", and his earlier work for Von Sternberg in "The Last Command". In real life, he was an enthusiastic endorser of Hitler, and made pro-Nazi films for Goebbels. After the war, of course, he was an untouchable and he never made another film after 1945. Like Professor Rath, he made a decision and suffered the consequences.