Katherine Schiff Illowy was one of ten children born to Mayra Anna Belha and Wolff Schiff. She was raised in Raudnitz, Bohemia, where her father was a prominent merchant. In 1845 she married rabbi Bernard Illowy, and two years later the first of her four children was born.

In the early 1850s, the family left for the United States because Bernard’s political sympathies had made it difficult for him to work in Germany. Their life in America was a rather itinerant one as Bernard, the leading American Orthodox rabbi of the day and staunch opponent of Reform Judaism, moved from one congregation to the next: New York, Philadelphia, Saint Louis, Syracuse, Baltimore, New Orleans (for the duration of the Civil War) and finally Cincinnati. Tired of moving, perhaps, Katherine would remain in Cincinnati for the rest of her life, outliving Bernard by seventeen years.