Relocating to Boston in the mid-1820s, he became a clothing retailer and in 1828 married a woman named Eliza. They had one son, Edward (or Edwin) Garrison Walker, born after David Walker's death in 1830. An active figure in Boston's African American community during the late 1820s, David Walker had a reputation as a generous, benevolent person who sheltered fugitives and frequently shared his in-come with the poor. He joined the Methodist Church and in 1827 became a general agent for Freedom's Journal, a newly established African American newspaper. During the two years of the newspaper's existence, he regularly supported the New York City-based publication, finding subscribers, distributing copies, and contributing articles. He was also a notable member of the Massachusetts General Colored Association, an antislavery and civil rights organization founded in 1826. In lectures before the association, Walker spoke out against slavery and colonization, while urging African American solidarity.
In September 1829, he published David Walker's Appeal. In this pamphlet, which quickly went through three editions, he fiercely denounced slavery, colonization, and the institutional exclusion, oppression, and degradation of African peoples. His Appeal was a militant call for united action against the sources of the “wretchedness” of African Americans,