Personality characterizes an individual through a set of traits that influence his or her behavior. We propose a model of personality that can be used by intelligent, automated actors able to improvise their behavior and to interact with users in a multimedia environment. Users themselves become actors by exercising high-level control over their own intelligent agents. We propose different dimensions of personality that are based on the processes that intelligent agents usually perform. These dimensions are rich enough to allow the specification of an interesting number of characters able to improvise and react differently although they are put in the same context. We show the influence that the personality traits have on an actor’s behavior, moods and relationships. An application of the Computer Virtual Theater, the Cyberoaft, is used to test our model.