Jack was an only child to active socialist and freethinker parents. His grandparents had immigrated from central and eastern Europe to escape oppression and poverty. Like his parents, the child Jack was a radical nature-worshiper who distrusted organized religion.[1] He met Esther Rhys Williams at Munroe High School, in the early 1930s, and the two married in 1939. The marriage would produce two children and end in divorce in the early 1970s.
While in Chicago, Jack led efforts and rallies to prevent the United States' entry into World War II and fought racial segregation. He was active in the publication of Rochester's No-War News and the Fellowship of Reconciliation and helped organize the anti-war 1942 Chicago sit-in and the anti-segregation Journey of Reconciliation.
From 1942 to 1943, he served as a Unitarian minister in Lawrence, Kansas, where he spoke out against Lawrence's "violently anti-Negro and anti-labor" stance.[1] He was the executive secretary of Chicago Council Against Racial and Religious Discrimination from 1943 to 1948, and from 1948 to 1959 served as the minister of the Unitarian Church of Evanston, Illinois.
Jack co-founded and was the associate director of the American Committee on Africa from 1959 to 1960, co-founded and served as executive director to the Congress of Racial Equality and National Committee for a Sane Nuclear Policy (SANE) from 1960 to 1964, and directed the Social Responsibility Department of the Unitarian Universalist Association in Boston from 1964 to 1970. In that role, Jack convened the "Emergency Conference on Unitarian Universalist Response to the Black Rebellion" as an effort toward Black Empowerment in the UUA.[2] From 1970 to 1983, he was the secretary general of the World Conference of Religions for Peace in New York. Simultaneously, from 1973 to 1984, he chaired the NGO Committee on Disarmament, Peace and Security at the United Nations Headquarters.[3]
In 1984, he served as a minister once again in Winnetka, Illinois, a position he would hold until 1989. That same year, he was awarded the Niwano Peace Prize.[1]
In the late 1980s, Jack retired from official positions and moved to Swarthmore, Pennsylvania, where he authored two books and continued to be active in various peace and human rights organizations.[3] He was awarded the Jamnalal Bajaj Award in 1992.[4] He also remarried, to German Quaker Ingeborg Belck.[1] He died of cancer in Swarthmore in 1993. Jack's autobiography was published posthumously in 1996 as Homer's Odyssey: My Quest for Peace and Justice.[3][5]
