Warner is highly influential in the fields of early American literature, social theory, and queer theory. His first book, "The Letters of the Republic: Publication and the Public Sphere in Eighteenth-Century America", established him as a leading scholar in Early American literature, print culture, and public sphere theory. He later became a public figure in the gay community for his book "The Trouble with Normal", in which Warner contended that queer theory and the ethics of a queer life serve as critiques of existing social and economic structures, not just as critique of heterosexuality and heterosexual society. His most recent work, "Publics and Counterpublics" is a collection of essays on the politics of communication in advanced capitalistic societies, or Habermasian public sphere theory.