In Shakespeare's Macbeth, why is Macbeth a tragic hero?

Shakespeare's tragic heroes have certain circumstances and personal qualities in common. They are all men of power and high social status, well respected by others. However, each has a character flaw--a "fatal flaw"--that leads to his downfall. The tragic hero is unaware of this flaw in his character until it is too late to save himself. Once his destruction becomes obvious, he does not give up; he fights to reverse his fortunes and regain his position. Finally, as the tragic hero is destroyed, Shakespeare gives us a final glimpse of the great man he once was. This reminds us of how far the hero has fallen and emphasizes the tragedy of his destruction.

Macbeth's character is developed precisely according to this model. He is a Scottish general, an extraordinarily loyal, strong and brave supporter of King Duncan. He holds high social position as Thane of Glamis and also becomes Thane of Cawdor, a high honor bestowed upon him by his King. Macbeth is well respected. However, hidden in his character is his fatal flaw, one of ambition. Once his ambition is aroused, he sets out on a path of destruction, murdering Duncan and others who stand in his way or threaten his power. When the tide turns against Macbeth and he is attacked by both Scottish and English armies, he chooses to fight rather than surrender. When he tries to avoid shedding Macduff's blood and acknowledges the sin of the slaughter of Macduff's family, we see some of the goodness that Macbeth used to possess. When Macbeth learns that he is not protected in battle with Macduff, he fights on. Shakespeare shows Macbeth, at the moment of his destruction, fighting as the strong and courageous warrior he once was. The tragedy of Macbeth's life is that a once admirable man became a monster because of the flaw in his own character; he destroyed himself.