Czerniaków was born on 30 November 1880 in Warsaw, Poland (then part of the Russian Partition). He studied engineering in Warsaw and Dresden and taught in the Jewish community's vocational school in Warsaw. From 1927 to 1934 he served as member of the Warsaw Municipal Council, and in May 1930 was elected to the Polish Senate. On 4 October 1939, a few days after Warsaw surrendered to Nazi Germany, Czerniaków was made head of the 24 member Jewish Council (Judenrat), responsible for implementing German orders in the new Jewish Ghetto. The Warsaw Ghetto was closed to the outside world on November 15, 1940.