Leendert is een zoon van Leon Aronson en Rebecca van Dam. Hij trouwde 17 juni 1908 met Sophia Bonewit (24 jaar), dochter van Nathan Bonewit en Grietje Bonnewit.
On 14 September 1945 the children and other relatives of Leendert Aronson placed an obituary for him and his wife Sophia Aronson-Bonewit in the Nieuw Israëlitisch Weekblad. According to the text in the obituary, Leendert Aronson and Sophia Aronson-Bonewit died 'a violent death' in Auschwitz. Leendert Aronson was 58 when he died and Sophia Aronson-Bonewit 60 when she died. Nieuw Israëlietisch Weekb…