in act 1 he meets 3 witches who prophesy that he will be awarded thane of cawdor and become king.
in act 1 he sends a letter lady macbeth explaining the witches prophecies
in act 2 he plots with his wife to murder duncan and assume the throne.
in act 2 he sees visions of a bloody dagger
in act 3 he arranges for banquo to be murdered because of the witches predictions that his children will be kings.
in act 4 he sends murders to macduffs castle to kill his wife and kids.
in act 5 he is murdered by macduff.
his ambitions lead him to murder his king and take the throne.