Maria von Trapp
At the start of the film, Maria is a young nun-in-training, but her sunny personality, love of music and the mountains, and her vivacious free spirit make her seem a little unsuitable for the deprivations and rigors of abbey life, in the eyes of the Mother Abess. She is steered instead to another job where she can use her skills and beliefs to guide and protect young children who have recently lost the mother, and whose father is very remote and militaristic. Maria is like a breath of fresh air in the von Trapp household, immediately raising everyone's spirits. She is loving towards the children and gives them the maternal and gentle discipline and structure that they need.
Maria loves music and she immediately brings music back to the villa. This is also very good for the Captain; he has not sung since his wife passed away, but joins in the singing with his children at a family gathering. Maria knows that singing is good for the soul. It also turns out to be lifesaving for the family as it is only because of their participation in the Salzburg Festival that they are able to flee the German occupiers and escape to Switzerland.
Maria is a strong and determined young woman with a sensible head on her shoulders. She is, however, rather instantly taken with the Captain. Initially feeling that this is wrong and that she should seclude herself from her feelings, she is again counseled by Mother Abess, and comes to realize that she needs to seek her own happiness. She is in love with the Captain and needs to accept this and confront her feelings head on; when she does so, she learns that they are reciprocated.
Captain von Trapp
A military man, and veteran of the Austrian navy, Captain von Trapp has taken to raising his children in the same way that he captained his men. They are disciplined with military precision, primarily because he does not know how to cope with his feelings of sadness since losing his wife. The joy has gone out of the Captain since he was widowed; he realizes that it is a long time since he sang with his family, but it is also a long time since he had music in his heart.
The Captain realizes that he has strong feelings for Maria once she has left the villa. He has a certain tenderness with her that seems at first glance out of character. He is an honorable man and does not try to change her mind, or elicit feelings from her that she is not ready to share with him. As soon as she returns he breaks off his engagement to the Baroness because he does not want to lie to her, or to himself.
The Captain is opposed to the Nazi regime and does not intend to join the navy again to fight in Hitler's military. He sees escape as the only option and courageously leads his family to safety in Austria. He is almost a lone voice amongst his friends and neighbors in feeling this way; most have supported Hitler unquestioningly and so it takes a great deal of backbone for him to stick to his beliefs in what is right, and find a new life for his family in a country that is not yet annexed by the Germans.
Baroness Elsa von Schrader
The Baroness is romantically involved with the Captain when we first meet her, and subsequently becomes his fiance; she does not seem to be a particularly warm woman where his children are concerned and there appears to be a distance between them, a false politeness that the children's father insists upon, as he also insists upon their kissing Elsa goodnight even when it seems forced and too deliberate.
Elsa is jealous of Maria from their first meetings because she can tell that the Captain is attracted to her. She identifies her immediately as a threat to her relationship so that when Maria is conflicted about her feelings for the Captain, and is considering returning to the Abbey, Elsa takes advantage of this and tells her that she should leave the villa at once and return to seclusion.
Max Detweiler
Detweiler is a family friend of the von Trapp's and also a friend of Elsa von Schrader. He is a theatrical agent and so always has an eye out for the next big thing that will make him alot of money. When he hears the children sing, he is immediately excited by the possibilities for them. He is quite determined that they attend the Salzburg Festival, which their father forbids. Fortunately for all concerned, he blatantly disregards the Captain's insistence that they do not attend the Festival; if not for Max, they would have no cover story for their escape.
Mother Abess
Mother Abess is in charge of the Abbey and is also in charge of the pastoral care of the abbey nuns. She is not nearly as rigid and strict as her position might suggest; she doesn't believe that Maria will be able to have the self-discipline to give up all the things she is passionate about, but rather than trying to insist that she does so, steers Maria in the direction of other ways in which she can serve God and still adhere to her calling. She is a tender woman who sees that Maria is in love with the Captain, and also sees that she should chase after what she believes will make her life complete.
Mother Abbess is extremely loyal to those in her care. She is instrumental in helping the von Trapp's escape the Nazis and is also courageous in facing down the brownshirts as they swarm through the abbey looking for the family.
Liesl von Trapp
Liesl is the oldest of the von Trapp children, and is particularly grateful for Maria's entry into her life, because she is at that age between older child and young woman, and particularly needs a mother figure in her life. She is starting to discover boys and is seeing Rolfe in secret. She warms to Maria immediately after Maria keeps secret the fact she saw Liesl sneaking back into the house after a forbidden date.
Rolfe
Rolfe is a pleasant young man who is rather smitten with Liesl von Trapp. The two are secretly dating and he is extremely respectful and thoughtful in his relationship with her. However, their relationship ends suddenly, not because it is discovered by the Captain, but because Rolfe is an enthusiastic supporter of Hitler, and after the annexation of Austria joins the Hitler Youth, becoming both domestic foot soldier and informant. He participates in the chase that ensues after the von Trapps escape, but is still dazzled enough by Liesl that he hesitates before sounding the alarm when he finds the family in their hiding place.
