In 1837, he was one of three founding members, with James Haughton and Richard Allen, of the Hibernian Antislavery Association.
Webb married Hannah Waring and they had four children Alfred, Richard, Deborah and Anne.
[3] Webb was one of the few Irish delegates at the 1840 Anti-Slavery Convention in London which attracted hundreds from the United States.
This time the subject was temperance and Webb's fellow delegate Richard Allen was one of the speakers.
Webb however showed no such false regard and they argued as equals in a way the Douglass hoped would be a precursor of the relationships that might exist across the races when slavery ended in America.