Early Life and Conversion
William Miller was born in Pittsfield, Massachusetts, in 1782 and grew up in the rural setting of Low Hampton, New York. As a young adult he moved to Poultney, Vermont, married Lucy Smith, and held local public offices.
During this period he drifted into Deism, but his wartime experience in the War of 1812, especially the Battle of Plattsburgh, reshaped his outlook. He eventually returned to Christian faith and began intensive Bible study.
Prophetic Study and Public Preaching
Miller's study of Daniel 8:14 and related prophecies led him to conclude that Christ's return was near. By 1818 he believed the Second Advent would occur within about twenty-five years, and after further private study he began public preaching in 1831.
His lectures spread rapidly through newspapers, pamphlets, and camp meetings. The movement that formed around his preaching became known as Millerism and drew tens of thousands across North America.
1844 and the Great Disappointment
Miller did not set every later date used by his followers, but his prophetic framework shaped the expectation centered on 1843-1844. When October 22, 1844 passed without the visible return of Christ, the movement suffered what became known as the Great Disappointment.
Miller publicly acknowledged disappointment while maintaining belief in Christ's soon return. His humility after failure became one of the defining marks of his legacy.
Lasting Influence
Miller died in 1849 at Low Hampton. Although he did not live to see later Adventist institutions develop, his movement directly influenced multiple Adventist bodies, including the Seventh-day Adventist Church.
His enduring contribution was the call to serious prophetic study and moral preparedness for the return of Christ.
Sources
Primary chronology and quotes in this profile are based on the Wikipedia article on William Miller (preacher) and linked references: https://en.wikipedia.org/wiki/William_Miller_(preacher)