Born in Van Wert, Ohio, Dale McMillen learned the hay, grain and feed business by toiling for his father at their grain elevator. By 1913, McMillen was elected President of the National Hay Association, the youngest President ever elected to that post. The McMillen Company was launched by him in 1916. It merged with the American Milling Company in 1929 to form Allied Mills with Dale McMillen serving as President.