Mrs. Clinton, who is Methodist, "has very fond childhood memories" of the second husband of her grandmother, Max Rosenberg, a Russian-born Jew, said Howard Wolfson, a spokesman for the first lady's Senate exploratory committee.
Wolfson said Thursday that he doesn't "expect it will have an electoral impact, and we don't see it in that context."
Mrs. Clinton's maternal grandmother, Della, married Rosenberg in 1933, seven years after she and Mrs. Clinton's grandfather, Edwin Howell, divorced, according to a weekly Jewish newspaper, The Forward.
They had filed a petition for Max to adopt Della's children, including Mrs. Clinton's mother, Dorothy, but the attempt failed. Max Rosenberg died in Los Angeles in 1984.
Mrs. Clinton angered potential Jewish voters last year by voicing support for a Palestinian state, but has recently told Jewish leaders she considers Jerusalem "the eternal and indivisible capital" of Israel.
She has also said she favors moving the U.S. Embassy for Israel from Tel Aviv to Jerusalem. The United States has never recognized Jerusalem as Israel's capital.