Martin Delany built a public career in medicine, journalism, abolitionism and Black political thought. In Pittsburgh he studied medicine through apprenticeship, treated patients and founded the newspaper Mystery in 1843. From 1847 to 1849 he worked with Frederick Douglass on the North Star. His admission to Harvard Medical School in 1850 ended after protests by white students forced him and other Black students to withdraw.

Delany increasingly argued that formal freedom in the United States could not guarantee security or equal opportunity. His 1852 book The Condition, Elevation, Emigration, and Destiny of the Colored People of the United States advocated Black self-reliance and considered emigration for political independence. He helped organise emigration conventions and moved his family to Canada. His novel Blake imagined resistance and insurrection across the slaveholding Americas, offering a different political vision from narratives centred on patient endurance.

In 1859 he travelled in West Africa with Robert Campbell and negotiated an agreement at Abeokuta for possible settlement and commercial development by African Americans. The project did not materialise. The Civil War redirected his efforts toward Union victory: he recruited Black soldiers, met Abraham Lincoln and received a major's commission in 1865, becoming the United States Army's first Black field officer. He subsequently worked for the Freedmen's Bureau in South Carolina.

During Reconstruction, Delany advocated economic independence and participated in state politics. He ran unsuccessfully for lieutenant governor in 1874 on an independent Republican ticket and later supported Democrat Wade Hampton, a choice that alienated many former allies. Service as a trial justice ended amid a fraud prosecution and imprisonment. He continued writing, medicine and business ventures before returning north. His changing alliances complicate interpretations of an unchanging programme of Black nationalism.