Polycarp Kusch was born on January 26, 1911, in Blankenburg, Germany, to John Matthias Kusch, a Lutheran missionary, and his wife, Henrietta. Polycarp's father brought the family to the United States in 1912.

Kusch, who became a naturalized citizen of the United States in 1923, attended public schools in Cleveland, and in 1927 matriculated at Cleveland's Case School of Applied Science (later renamed Case Western Reserve University), where he intended to study chemistry. He became a physics major instead, and received his B.S. in 1931. He continued his study of physics at the University of Illinois, where he held a graduate assistantship; he earned his M.Sc. degree in 1933 and his Ph.D. in 1936. While at the university, he met Edith Starr McRoberts, whom he married on August 12, 1935, and with whom he had three daughters, Kathryn, Judith, and Sara.

In 1937 Kusch became a research assistant to John T. Tate at the University of...