Linda is a loving and affectionate wife to Willy. She presents an image that she thinks is appropriate for a wife, which is that of a cheerful and living companion. She encourages both Willy and his sons to pursue their ambitions though she seems to recognize they are misguided.
Throughout the play, Miller indicates that her remarks are delivered "without criticizing" and "with patience." As Willy says early in the play, Linda is his "foundation and support." However, her primary role is perhaps that of a mediator between her sons and Willy, a situation that places a great deal of strain on her. She suspects throughout the play that Willy will do exactly what he winds up doing, i.e. committing suicide. As she tells Biff in Act I, Part 4, she has no illusions about Willy, but recognizes he is in a bad situation and needs the family's support:
I don’t say he’s a great man, but he’s a human being, and a terrible thing is happening to him. So attention must be paid.
Linda is among the play's most sympathetic characters, and though she is a strong woman, it is hard to escape the conclusion that she is victimized by the family's dysfunctional nature. She is not blameless, though, and perhaps being more brutally honest with her husband and sons would have helped matters.