In Shakespeare's Macbeth, how is Macbeth's ambition his hamartia?

At the beginning of the play,is described as a violent maniac, utterly fearless and
reckless in his blood-lust:

Disdaining fortune, with his
brandish'd steel,
Which smoked with bloody execution,
Like valour's minion
carved out his passage
Till he faced the slave;
Which ne'er shook hands, nor
bade farewell to him,
Till he unseam'd him from the nave to the chaps,
And
fix'd his head upon our battlements.

The response of
Kingto this terrifying conduct is all too predictable:

O
valiant cousin! Worthy gentleman!

As long ass furious
violence is employed in the service of his King, he is...