In the good old days of live TV, there were many of these shows - The U.S. Steel Hour was one, there was Playhouse 90, Schlitz Playhouse, Lux Playhouse, etc. They attracted big stars and were done expensively. In the costume drama "The Thief," the stars are Paul Lukas, Mary Astor, James Dean, Diana Lynn, and Patric Knowles. Pretty impressive.
Dean plays Fernand, a young man in love with the married Marie-Louise Voyson (Lynn) married to Phillipe (Knowles.) When money goes missing, Fernand admits to it, to his father's (Lukas) horror.
Dean doesn't have much to do, but I thought he was good. He's not an angry, rough teen here, but high-class French, and I think he acquits himself well and in period. If he seems awkward, I'm sure it's because of the nerves of live TV or lack of sufficient rehearsal.
As usual there were people who hated working with him; this time it was Paul Lukas. On East of Eden it was Raymond Massey. I'm seeing an older man pattern here.
I'm not sure Dean was really difficult or just liked to press certain people's buttons. I'm convinced that neither he nor Brando had the eccentric personalities they pretended to have. But if they could get away with it and call their self-indulgences the eccentricities of great actors, they would.
I would say if you have a chance, definitely see this and any of Dean's television work. There is so little of him available; these TV shows give more of an idea of the range he could have developed.