Portia is beautiful and clever; in fact, she is far more clever than the men around her. While men try to control or deceive her in different ways, she is able to outwit them all. She clearly has to be more clever than the men around her to defeat the patriarchal society in which she lives. For example, her deceased father decreed that the man she marries has to win in the casket game; to help her chosen man, Bassanio, win the game over a prince of Aragon and a prince of Morocco, she employs a group of musicians to play tunes that provide Bassanio with the right choice to win the game. While dealing with the other men who vie for her hand, who are all deficient in some way, she feigns politeness and acceptance while rigging the game to favor her chosen man. Later, she disguises herself as a lawyer named Balthazar to save the life of Bassanio's friend, Antonio, who has been locked up by Shylock. While playing the part of a man, she uses the observations of men she has known to carry out her role to perfection. She is far more intelligent than the men around her, and she uses her beauty, intelligence, and savvy to triumph in a male-dominated world.
First, Shakespeare does, in fact, have heroes, including Brutus in Julius Caesar, Edgar in King Lear, Hamlet, and Othello. Within The Merchant of Venice, Antonio is in many ways a noble and admirable character, and Bassanio, although imperfect, is certainly a sympathetic character.
Portia herself is a model Shakespearean heroine. Although an heiress, she is determined to marry for love rather than money, and shows herself strong, brave, and clever in pursuit of her goals. Her generosity in offering her dowry to Shylock shows that she is devoted and unselfish. Her stratagem to disguise herself as a lawyer, and her clever arguments at court show her not only to be intelligent but also quick-witted and capable of clever improvisation.
One aspect of both the play and the character of Portia that some modern critics find troublesome is its anti-semitism. To a modern audience the forced conversion of Shylock seems cruel and unnecessary, although within the logic of the play, it forms a way of reconciling him to the Christian community and also saving his soul.