Katie Mogulefsky became Katie Mogul upon her arrival, with her family, at Ellis Island, and Katie Feldman when she married Alec Feldman. (They later divorced.) They had a son, Percy, who died as a child, a daughter, Mollie, and another son, Jacob, whom they called Jake but who in adulthood preferred to be called Jack. Katie lived to meet one of Jack's daughters, Gail, but died before the birth of his second daughter, Janice Kate (named after her and her other grandmother).

Katie may have been born in Mogulefsky Podolsky, Ukraine. She may have had sisters.