Etzik Kreimer was born in Cherkass, in present day Ukraine, and immigrated to the United States in 1912 by way of Berlin, Germany. After his arrival, he changed his name to Isadore B. Kreimer.
Isadore B. Kreimer served in the U.S. Army in the 80th Infantry Division (1917-1919) during World War I before becoming a U. S. citizen in 1927. He married Mildred Weinberg in 1924 and settled on Woodmont Street in Squirrel Hill. That same year, he opened Royal Credit Clothing Company at 713 Liberty Avenue in downtown Pittsburgh. The store allowed customers to purchase higher-end clothing on credit and pay in installments.
Isadore and Mildred Kreimer had one child, Patricia. Patricia Iris Kreimer (1925-2006) attended local schools. She was confirmed at Rodef Shalom Congregation in 1941 and graduated from Allderdice High School the following year. Kreimer attended Northwestern University until 1943, when she transferred to the University of Pittsburgh. She graduated from its Retail Training Bureau in 1946. Patricia Kreimer married jeweler Ralph L. DeRoy on October 2, 1942. They had two children, Al K. DeRoy and Diane DeRoy.