Dorothy Hammerstein spouses to marry in 1929. Oscar also had two children from his first marriage: William Hammerstein and Alice Mathias. His marriage to Dorothy lasted until his death in 1960. They had a son together, James Hammerstein. Between the 1930s and the 1950s she operated Dorothy Hammerstein Inc, a high-profile interior design business, with clients on both coasts of the United States. In 1949, along with her husband and the novelists Pearl S. Buck and James A. Michener, she was a founder of Welcome House, an organization that facilitates the adoption of children of American and Asian parents. From its inception
Hammerstein House Hollywood Historical Society in honor of his late wife Vera Hammerstein. It was his wish that the home be operated as a museum and he contributed many artifacts of his life which form much of the display there. Items on display include Hammerstein's WWI Air Force uniform. The ashes of the home's owners Clarence and Vera Hammerstein reside at the house in two large urns. It was added to the National Register of Historic Places on February 15, 2005. The home is operated as a historic house museum by the Hollywood Historical Society and contains artifacts of the Hammerstein's life.