Good question! The identity of the title character has been debated for years, and as if that is not enough controversy, the audience has to decide if the hero of the play is even the title character. Here are several options:
1. Shylock--although the play is a true Shakespearean comedy, some critics have argued that it meets many of the qualifications of a tragedy. If you think of Merchant as a tragedy, then Shylock is the tragic hero. While Shylock is not respected socially, he is well known as a businessman and experiences a tremendous downfall (he loses his livelihood, his daughter, his pride, and his faith).
2. Antonio--he is an actual merchant because of his venture business and his involvement in trade. The play begins with his moodiness, and Shakespeare never discloses what has caused Antonio to be so melancholy.
3. Portia and Bassanio--together, this couple makes up the hero of the play as a comedy. All the conflict in the play, including the three plots (the casket, bond, and ring plots) involve Bassanio, and Portia eventually participates in the bond plot when she questions Shylock. The couple marries in the course of the play and eventually lives happily ever after--a requirement of a Shakespearean comedy.