Smith studied at Glasgow University. Hearing Edward Irving preach in 1828, he became a millenarian and associated with followers of Joanna Southcott. For a couple of years he became a Christian Israelite under John Wroe. He moved to London in 1832, and his millenarianism turned socialist. He translated Saint-Simon, edited Robert Owen's journal Crisis, and wrote for James Morrison's Pioneer.
Smith edited The Shepherd 1834-5 and 1837-8, and wrote leaders for the Penny Satirist. In 1843 he founded a penny weekly, the Family Herald, which at one point approached a circulation of half a million.