Frederik Polak was a son of Meijer Polak and Julia Parser. He married in Amsterdam on 3 August 1910 to Grietje Asscher, daughter of Jacob Asscher and Jochebeth Tal. The couple had five children: Meijer, who passed away just 1 year old, Jacob, Julia, Betsie and Elisabeth Alida.
City Archive of Amsterdam, archive card of Frederik Polak.