How is America's Chief of State and Head of Government different from Australia's Chief of State and Head of Government?

Australia's Head of State is the Queen of Australia, The President is both the head of state and head of government of the United States of America, and Commander-in-Chief of the armed forces

The Head of State is the greatest representative of a State.

The personification of the state's legitimacy and its continuity is in the figure of the Head of State. He is the one who must embody the spirit of the nation for his own people, as well as for the world. For that, the Constitution of each country defines the guidelines that characterize the presence of the Head of State, but, in general, and because he is the highest public representative, he is responsible for maintaining the continuity of the exercise of powers.

The Head of State is a public representative who is present in all forms of government. When it comes to a monarchy, he is the monarch. When it comes to a republic, he is the president. However, in countries where the government is presidential, the Head of State also assumes another role, that is, Head of Government.