The Roman Catholic Church was the only organized religion in Michigan until the 19th century. Detroit's St. Anne's parish, established in 1701, is the second-oldest Catholic parish in the country. In 1810, a Methodist society was organized near Detroit. After the War of 1812, as settlers poured in from the east, Presbyterian, Congregational, Baptist, Episcopal, and Quaker churches were founded. The original French Catholics, reduced to a small minority by the influx of American Protestants, were soon reinforced by the arrival of Catholic immigrants from Germany, Ireland, and, later, from eastern and southern Europe. The Lutheran religion was introduced by German and Scandinavian immigrants; Dutch settlers were affiliated with the Reformed Church in America. The first Jewish congregations were organized in Detroit by German Jews, with a much greater number of eastern European Jews arriving toward the end of the 1800s. The Orthodox Christian Church and the Islamic religion have been introduced by immigrants from the Near East during the 20th century.

Michigan had 2,019,926 Roman Catholics in 2000. Among Protestant denominations, the largest groups were the Missouri Synod Lutherans, with about 244,231 adherents, and the United Methodists, with about 222,269 adherents. Evangelical Lutherans numbered about 160,836 adherents. The Christian Reformed Church had about 112,711 members and the Presbyterian Church USA had 104,471. The Seventh Day Adventists, who had their world headquarters in Battle Creek from 1855 to 1903, numbered 37,712 in 2000. The Jewish community had about 110,000 members. Over 5.7 million people (about 58% of the population) were not counted as members of any religious organization.