William Henry Harrison attended St. John's Episcopal Church while he was President.
From: Peter Roberts, "William Henry Harrison" page in "God and Country" section of "Science Resources on the Net" website (http://www.geocities.com/peterroberts.geo/Relig-Politics/WHHarrison.html; viewed 29 November 2005):
Religious Affiliation: Episcopalian
"We admit of no government by divine right, believing that so far as power is concerned the Beneficent Creator has made no distinction amongst men; that all are upon an equality, and that the only legitimate right to govern is an express grant of power from the governed." -- Inaugural Address, 4 March 1841
"I deem the present occasion sufficiently important and solemn to justify me in expressing to my fellow-citizens a profound reverence for the Christian religion and a thorough conviction that sound morals, religious liberty, and a just sense of religious responsibility are essentially connected with all true and lasting happiness; and to that good Being who has blessed us by the gifts of civil and religious freedom, who watched over and prospered the labors of our fathers and has hitherto preserved to us institutions far exceeding in excellence those of any other people, let us unite in fervently commending every interest of our beloved country in all future time." -- Inaugural Address, 4 March 1841