Levie Ketellapper was a son of Salomon Ketellapper and Judith Sweijd, a family with six more children: Elisabeth, Susanna, Vrouwtje, Debora, Marie and Nathan.
Levie married in Amsterdam on 5 December 1923 to Betje Hammelburg.
City Archive of Amsterdam, family registration-card of Salomon Ketellapper and archive card of Levie Ketellapper.