In the early 1950s, after earning a master’s degree from Atlanta University, Williams worked as a research chemist for the U.S. Department of Agriculture and was also ordained as a minister. During this time, Williams wed Juanita Terry as well. The couple would have five children together and would adopt an additional four.
During the late 1960s, at King’s urging, Williams collaborated with the Coordinating Council of Community Organizations on the Chicago Campaign. In 1968, he returned to the South as field director for the SCLC’s Poor People’s Campaign, and in April of that year witnessed King’s devastating assassination. In the 1970s, Williams was elected executive director of the SCLC.