 Bell was the 13th Isaac Bell of his line, with his ancestor landing on the shores of the New Haven colony in 1640.His two younger brothers were Louis Valentine Bell (1853–1925) and Edward Bell (1860–1902), who married Helen A. Wilmerding (1856–1936), a daughter of Henry A. Wilmerding.His sister was Mrs. James L. Barclay (d. 1893).