Oh My! We get questions frequently about whether a particular surname is Jewish. Any name can be Jewish. Exclusively Jewish surnames are very rare. Goldberg, for instance, is not exclusively Jewish. A lot of names in the U. S. are viewed as Jewish as a large portion of immigrants with certain names were Jewish while back in their country of origin the same name was use by Jews, Christians and village atheist.
Also understand a Jew by the Talmud is defined by the mother, not the father. Surnames traditionally, in western countries that is, usually come from the father. This means a person could be born an O’Brien and be Jewish by birth.
Here is a great link: