No, Isaiah was a prophet. You may be thinking of Nehemiah. He was a cup bearer to King Artaxerxes the Persian King where Nehemiah and his countrymen were in exile.
See Nehemiah 2:1.
He didn't "have" to. It was considered a great honor to be a cupbearer to the king in his time.
The word "cupbearer" is in the King James Version of the Bible 1 time. It is in 1 verse.
Zeus's cupbearer
The cupbearer and the baker were two fellow prisoners who had dreams that troubled them. Joseph interpreted their dreams, which led to the cupbearer being reinstated to his position in Pharaoh's court. The cupbearer promised to remember Joseph when he was released, but forgot about him until Pharaoh needed a dream interpreter, which eventually led to Joseph's release from prison and rise to power in Egypt.
ganymede
Ganymede, though to be clear, the moon is only named after Ganymede; the cupbearer of the gods wasn't a moon in Greek mythology.
Sharer, preparer, wearer, reign of terror
Ganymede.
There is no Hebrew word for cupbearer. You could describe it as מלצר המגיש יין (which means "waiter who brings wine"). Sometimes, the Biblical character from the story of Joseph is mistranslated as "cupbearer" שר המשקים (which literally means "chief of drinks").
Nehemiah, as he was the King's cupbearer
Ganymede.
As the cupbearer of the Greek gods and goddesses who served ambrosia at the heavenly feast.