When Johannes Cornelis Houtzager was born on 10 January 1866, in Vlaardingen, South Holland, Netherlands, his father, Coenraad Hermanus Dijkman, was 22 and his mother, Maria Houtsager, was 22. He married Rosaliena Janeta Marie Roosmalen on 5 May 1886, in Vlaardingen, South Holland, Netherlands. They were the parents of at least 10 sons and 5 daughters. He died on 19 March 1949, in Nijmegen, Gelderland, Netherlands, at the age of 83.