Joseph was born in the royal line of King David, but in his time the descendents of David no longer held power or wealth. He left his ancestral home of Bethlehem in Judea to become a builder and carpenter in the town of Nazareth in Galilee.
There he met Mary and became engaged to her. When she became pregnant before their marriage, he was uncertain as to what he should do. He finally decided to break off the engagement in accordance to the Law; but do to so quietly, so that she would not be subjected to charges of adultery and quite possibly a death sentence. However, an angel appeared to him in a dream and explained to him that God Himself was the father of Mary’s child, and that Joseph should not be afraid to marry her. Joseph accepted the angel’s message and the will of God and married Mary. After Mary’s son was born, Joseph named him Jesus, as he and Mary had been told by the angel. He raised Jesus as his own son, and likely trained him in carpentry. The Gospels make no mention of Joseph during Jesus’ adulthood, and so it is likely that he died before Jesus’ ministry began.
By marrying Mary, despite her pregnancy, and by accepting and naming Jesus, Joseph became Jesus’ father in the eyes of the Law; and by raising Jesus and caring for Him, he became his father in all ways but one. Therefore, while God is truly the Father of Jesus, Joseph can also be called His father. The Gospels call Joseph a “just” and “righteous” man, and his righteousness can be shown in his acceptance of God’s will, despite inconvenience and public scandal; the care he showed to his wife and Son; and his example, reflected in his Son.