If I was casting the role of Don, the characteristics I believe the actor would need to have are cockiness because the character of Don is very cocky and kind of like a Mr. know-it-all. He is very into himself, and his looks. He would also need to have a soft sweet side, because he shows that side with Kathy. This role was cast very well in the film I think. I think this because Don plays his part very well.
If I were casting the role of Don, the actor would need to be charismatic and charming . I think this role was cast well in the film. The actor confidently portrays Don as an arrogant yet charming and charismatic character (as, I believe, was intended).
