Paul’s father was born in 1884 in the small village of Blankenberg, Germany. For many years his family had worked in the local paper mill. Because of an emerging musical talent, Karl Stumpf left Blankenberg at the age of 14 to study his chosen instrument, the clarinet. As a professional musician—his instrument was the bass clarinet—Karl was for some years a member of the Staatsoper Unter den Linden in Berlin. In 1907 Karl Muck, conductor of the Boston Symphony Orchestra, invited Paul’s father, at that time only 23 years old, to join the orchestra as its bass clarinetist. His father accepted the position and together with 17 other German orchestra members became an integral part of the Boston Symphony. Karl Stumpf made frequent professional and personal trips to Germany. On October 2, 1914, en route to New York on the SS Noordam he met his wife-to-be, Annette Schreyer, who was a passenger on the same ship. The young couple entered into a shipboard romance, which culminated in their marriage in Boston on November 7, 1914.
When the United States entered World War I in 1917, a violent anti-German antagonism spread throughout America. One of its victims, Karl Muck, was arrested and jailed as a German spy on March 27, 1918, and by June 24, 1918, eighteen German members of the Boston Symphony Orchestra, including Karl Stumpf, were dismissed. Without an income and any hope of securing a similar position with an American orchestra, and with a growing family (Paul’s brother Felix had been born on February 10, 1917, and Annette Stumpf was pregnant with Paul) his father became withdrawn and greatly depressed until on the evening of December 13, 1918, he committed suicide. Ironically, on December 14 his mother received a letter addressed to her husband from Walter Damrosch, then conductor of the New York Symphony Orchestra, inviting Karl Stumpf to join the orchestra as its bass clarinetist.