Benjamin Slager was married to Lena de Vries. The couple had a daughter Aaltje Henriëtte and a son Abraham. The family lived at 4 Trekweg in Winschoten. Aaltje Henriëtte Slager was a shop assistant.
Benjamin Slager worked for the postal service. As a violinist, he played the music that accompanied silent movies.
In addition, a Jokos file (number 54264) on this family is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.