Son of Amoz (not the prophet Amos). Tradition says he was of royal blood, perhaps a cousin to King Uzziah. He had easy access to the kings of Judah (Uzziah, Jotham, Ahaz, Hezekiah).
Unlike the rugged Elijah or the rural Amos, Isaiah was a city man—urbane, educated, and wealthy. He lived in Jerusalem and was married to a "prophetess."
He was formed by National Crisis. He saw the Northern Kingdom fall to Assyria. He saw the moral rot of his own people hidden under religious rituals. He knew the system was broken from the inside.