Barr lets us know he grew up in a loving home, a product of a Catholic education, a player of the bagpipes. He attended the Horace Mann school in Riverdale, an affluent part of the Bronx. As Barr notes, the school was liberal and predominately Jewish.
https://www.theguardian.com/books/2022/mar/12/one-damn-thing-after-another-review-bill-barr-donald-trump-attorney-general
Also Bill Barr's grandparents and Dad are Jews.