John Wesley was born in 1703 in Epworth, Lincolnshire, the fifteenth child of Samuel Wesley, an Anglican rector, and Susanna Wesley, whose disciplined piety left a lasting mark on her son's spiritual formation. Educated at Christ Church, Oxford, Wesley was ordained as a Church of England priest and later joined a small student society at the university—nicknamed the "Holy Club" by critics—where members including his brother Charles practiced methodical prayer, fasting, and works of charity. The mockery embedded in that nickname would eventually lend a movement its name.
Wesley's faith underwent a decisive turn on the evening of May 24, 1738, when, at a meeting on Aldersgate Street in London, he heard a reading from Luther's preface to the Epistle to the Romans and described his heart as feeling "strangely warmed." This experience of assurance did not create his faith but clarified it, and within a year he had begun the open-air preaching that would define the rest of his long life. Barred from many parish pulpits, he took his message to fields and market squares, traveling an estimated 250,000 miles on horseback across Britain and preaching more than 40,000 sermons over five decades.
Wesley's theology emphasized the universal availability of grace, the possibility of entire sanctification, and the inseparability of personal holiness from social responsibility. He established schools, dispensaries, and lending societies for the poor, published extensively on medicine and theology alike, and in 1787 wrote a letter to William Wilberforce condemning the slave trade in unsparing terms. He organized his converts into small accountable societies that preserved revival's fruit where institutional churches had not always followed.
Wesley died in 1791, having never formally left the Church of England, yet the movement he shaped crossed into a global communion and left a permanent imprint on evangelical Protestantism's understanding of grace, holiness, and the care owed to the poor.