The name probably means, “Given by Ra (the sun god)”.
Potiphar, to whom Joseph was sold as a youngster (Gen. 37, 39), is called sar hatabbachim, “captain of the guard”.
He is also called saris, which is normally a eunuch, but in some contexts it means a courtier or government official (e.g. Jer. 39:3).
When Potiphar’s wife tried to seduce Joseph and then accused him of attempting to rape her, Potiphar put Joseph in prison, possibly not entirely believing his wife’s story but dutybound to take her side.
According to the Midrash he later apologised and explained that he had acted to protect his wife’s reputation and to save his children from stigma.
Rabbinic tradition is not entirely well disposed towards Potiphar. He is criticised for his idolatry and regarded as identical with Poti-phera, priest of On (Gen. 41:45); it is said that when his promiscuity resulted in illness he left his government post and became a priest in the temple of On.
There is also a suggestion that he was bisexual and bought Joseph in order to commit sodomy with him, but God or the angel Gabriel intervened and prevented this from happening.