Izak Lievendag was the son of Levie Lievendag and Betje Lievendag. He was married to Sophia Zeehandelaar, daughter of Marcus Samson Zeehandelaar and Dina Noach.
Izak Lievendag was imprisoned on 31 July 1942 and brought to Camp Haaren, from where he was transferred to Camp Amersfoort on 7 October 1942. From there Izak was deported to Mauthausen, where he was killed on 16 November 1942.
Archive Jewish Council, registration card Izak Lievendag; website Gedenkplaats Haaren (Memorial Haaren) http://gedenkplaats-haaren.nl/gevangenen-gijzelaars/joden/ and an addition of a visitor of the website.