What can we conclude about Antonio's character in Shakespeare's The Merchant of Venice?

Antonio, like most human beings, has a mixed character. We can admire him for his loyalty to Bassanio and his love for this friend. Whether the relationship is homoerotic or not, Antonio is willing to do anything to help this beloved young man. We can also admire Antonio as a successful merchant, willing to send his ships on risky ventures to get merchandise. This risk-taking extends to the loan he takes out from Shylock, confident that one of his ships will come to port before the loan is due to be repaid.
Antonio is confident, generous, loyal, a successful businessman, and willing to take risks. But he is also anti-Semitic, and Shylock resents a long history of insults and even low-scale violence from this merchant. Antonio is kind to his friends, but he is never kind to Shylock, even working to force this devout Jew to convert to Christianity at the end of the play.
We can also question whether Antonio is overconfident when he blithely agrees to the loan terms set up by Shylock. It seems that Antonio has grown so used to success that he is unable to imagine it not continuing to come his way. By the end of the play, however, he has received a warning call.

Antonio is one of the more important characters in Shakespeare's The Merchant of Venice. He is portrayed as a wealthy merchant who is well-respected in the city of Venice. He is intended to be admired for his role as a mentor and father figure to the rather imprudent Bassanio. Antonio is portrayed as loyal and self-sacrificing, willing to risk the loss of a pound of flesh for his young friend.
Close examination of his character, though, makes him somewhat less admirable. First, something many modern readers will find disturbing is his virulent antisemitism, behavior that underlies Shylock's insisting on such a harsh penalty. Antonio's treatment of Shylock shows a vindictive side to his character and religious and ethnic bigotry.
Next, Antonio's cash flow crisis makes the audience wonder if he is an imprudent merchant, prone to excessive risk taking and acting on impulse. His providing security to Bassanio to help Bassanio win the hand of a rich wife is problematic; outside of romantic drama, a good mentor would suggest that Bassanio curtail his expenses and get a job. Some critics have suggested a possible homosexual relationship between Antonio and Bassanio to account for the way in which Antonio seems so recklessly and impulsively self-sacrificing, though others argue that close male friendships with strong emotional overtones were common in this period and do not necessarily entail homosexual relationships.