Leo Walder Schwarz was born in New York City in 1906. He distinguished himself as a high school athlete and winner of the Gold Medal for Excellence in History and Literature at Twonsend Harris Hall. He attended Harvard University, where he specialized in Classical and Semitic Literatures and Religious Philosophy. Among his mentors was Professor Harry A. Wolfson, about whom Schwarz would later write a biography (Wolfson of Harvard, published posthumously in 1978). While still a student, Schwarz edited the Avukah Annual and Young Judean magazines.

Schwarz first received national attention for the publication, in 1935, of the Jewish Caravan. This collection of stories would become a classic of Jewish literature and be reprinted 15 times during Schwarz's lifetime. He was also the editor of Equality magazine and the Menorah Journal. In all, Schwarz would publish 14 books, collections, and anthologies.

During World War II, Schwarz served in Patton's 3rd Army, where he recieved a battlefield commission in the Normandy campaign. Following the war, he was named director of the American Jewish Joint Distrubution Committee (JDC), which was tasked with the resettlement and repatriation of displaced persons. From 1946 to 1947, Schwarz transformed the JDC from providing basic necessities of life to assisting displaced Jews with emigration, rehabilitation, and psychological counseling. He wrote three books about this period, The Root and the Bough (1949), The Redeemers (1953), and Refugees in Germany Today (1953).

Schwarz traveled widely, aiding the (New York-based) American Friends of the Hebrew University in Jerusalem, and serving as a liasion between American universities and that institution from 1948 to 1949. Having long supported student and Zionist groups in South Africa, Schwarz traveled there in 1960 to teach for a year at the University of Stellenbosch. From 1960-1962 and again from 1965-1966, Schwarz was a Visiting Professor of Judaic Studies at The University of Iowa's School of Religion. He was appointed Professor of Religion at Carleeton College for the 1966-1967 school year.

Schwarz recieved Hadassah's Myrtle Wreath Achievement Award in 1967. He died shortly thereafter, on December 1st, 1967, following a prolonged illness, at Veterans Hospital in New York. His funeral was held on December 4th.

Schwarz was survived by his wife of many years, Ruth Newman Schwarz. She was a partner in many of her husband's post-war activities and arranged for the donation of this collection to The University of Iowa following his death. Ruth Schwarz died in 1989.

In addition to the works mentioned above, Schwarz wrote or edited Three Translations (1933), Zionism and Palestine (1934), A Golden Treasury of Jewish Literature (1937), Memoirs of My People (1943), Great Ages and Ideas of the Jewish People, Feast of Leviathan (1956), Psychiatry and Religious Experience (1958), The Menorah Treasury (1964), and Human Values in Jewish Literature (1965). In addtion to these, he authored more than 150 papers, articles, and reviews. he died while working on the first volume of a one-man translation of the Hebrew Bible.