When Oscar Karpen was born on 24 June 1859, in Wongrowitz, Posen, Prussia, Germany, his father, Moritz "Morris" Karpen, was 35 and his mother, Johanna Cohen, was 24. He married Mary Simons on 20 December 1884, in Chicago, Cook, Illinois, United States. They were the parents of at least 1 son and 2 daughters. He died on 28 June 1953, in Chicago, Cook, Illinois, United States, at the age of 94, and was buried in Chicago, Cook, Illinois, United States.