Underwood continued his highly critical and public remarks both against former Confederates and their sympathizers (who had regained power in the state), and in favor of African American suffrage.
Underwood also served as one of 5 delegates from Henrico County (Richmond, although he did not live in either the city or county), at the Virginia Constitutional Convention of 1868, the first legislative body in the Commonwealth's history to include African-American delegates (20 served).