The concept of God varies across different interpretations of Judaism and Christianity.
In Judaism, God is understood to be a singular, eternal being who is the creator and source of all existence. God is not considered to have a physical form or gender.
In Christianity, the concept of the Trinity states that God is a single being existing in three co-equal persons: the Father, the Son (Jesus Christ), and the Holy Spirit. Jesus is considered to be the Son of God, and is both fully divine and fully human.
Whether God is "Jewish" is a complex question. In Judaism, God is the God of the Jewish people, who entered into a covenant with Abraham and established the laws and commandments that define Jewish life. Jesus was born Jewish and lived his life as a Jew. However, Christians believe that Jesus is the Son of God and that through him, people of all nations can have a relationship with God.
Ultimately, the answer to your question depends on your theological perspective.