He was a founder and served as National Chairman of the Medical Committee for Human Rights, which was formed in June 1964 to provide medical care for civil rights workers, community activists, and summer volunteers working in Mississippi during Freedom Summer. Quentin Young and MCHR also volunteered and helped set up Black Panthers and Young Lords health clinics and provided emergency medical care to protesters at the 1968 Democratic National Convention in Chicago. In October 1968 he was called to testify before the House Un-American Activities Committee about his knowledge of the DNC protests.