A tragic hero is the character in a tragedy that experiences a downfall because of some kind of flaw. This flaw is called the tragic flaw. Antigone is considered the hero of the play, and she has many tragic flaws which lead to her downfall.
One of Antigone's tragic flaws is her loyalty to the gods and, conversely, her disloyalty to King Creon. At the beginning of the play, Creon puts out an order that Antigone's brother, Polynices, may not be buried because he was a traitor. This is unacceptable to Antigone, and she is determined to honor the gods and give her brother a rightful burial, even if it means being executed for disobeying Creon's orders. Antigone's determination to honor the gods and her brother is one of her tragic flaws.
Antigone's stubbornness is another of her tragic flaws. She fails to see more than one side of the situation. To her, burying her brother is the most important thing. She doesn't think about how it might affect her sister, Ismene, who tries to convince her to back down and follow Creon's orders. She doesn't think about how it will affect Haemon, her fiance and Creon's son. She is too stubborn to see that it might be for the good of everyone involved to give into Creon's orders and let her brother's body lie where it stays.
Ultimately, what makes Antigone a tragic hero in this play are the traits she possesses which lead to her downfall. It is not necessarily her actions, but her convictions and values which cause her to be such a tragic figure.
Antigone ended up in utter defeat, hubris(pride) she had too much pride of what she did on disobeying the decree therefore causing her death.