Shalom.
Certainly he was still a Jew, a Hebrew and of the tribe of Benjamin. A Pharisee. This never changed. What changed was that he was converted. He later became a Christian if he was in Antioch or taught others to become Christians.
Acts 19:34 KJV - But when they knew that he was a Jew, all with one voice about the space of two hours cried out, Great [is] Diana of the Ephesians.
Acts 21:39 KJV - But Paul said, I am a man [which am] a Jew of Tarsus, [a city] in Cilicia, a citizen of no mean city: and, I beseech thee, suffer me to speak unto the people.
Acts 22:3 KJV - I am verily a man [which am] a Jew, born in Tarsus, [a city] in Cilicia, yet brought up in this city at the feet of Gamaliel, [and] taught according to the perfect manner of the law of the fathers, and was zealous toward God, as ye all are this day.
1 Corinthians 9:20 KJV - And unto the Jews I became as a Jew, that I might gain the Jews; to them that are under the law, as under the law, that I might gain them that are under the law;
Galatians 2:14 KJV - But when I saw that they walked not uprightly according to the truth of the gospel, I said unto Peter before [them] all, If thou, being a Jew, livest after the manner of Gentiles, and not as do the Jews, why compellest thou the Gentiles to live as do the Jews?
Shalom.
Jacob