Earl Boyea was born in Pontiac, Michigan, the eldest of the ten children of Earl and Helen Boyea, Sr. He was raised in Waterford and attended church and school at Our Lady of the Lakes as a child. He studied at Sacred Heart Seminary High School from 1965 to 1973, obtaining his bachelor's degree in history, then he traveled to Rome, where he studied at the Pontifical North American College and Pontifical Gregorian University (1973–1977), earning his bachelor's degree in sacred theology from the latter in 1976.
He was ordained to the priesthood by Bishop Joseph Imesch on May 20, 1978, while serving as a deacon at St. Benedict Church in Pontiac. Boyea then served as associate pastor of St. Michael the Archangel Parish in Monroe until 1979, and returned to the Gregorian in Rome, from where he obtained his Licentiate in Sacred Theology in 1980, with a thesis entitled: "Christology in Galatians". Upon his return to the United States, Boyea was associate pastor of St. Timothy Parish in Trenton until 1984, whence he earned his master's in American history from Wayne State University, with a thesis entitled: "John Samuel Foley, Third Bishop of Detroit: His Ecclesiastical Conflicts in the Diocese of Detroit, 1888–1900".
In 1986, he was named Temporary Administrator of St. Christine Parish in Detroit. Boyea obtained his PhD in Church history from the Catholic University of America in Washington, D.C. in 1987, and served as a weekend assistant at St. Joseph Parish in Lake Orion (1987–1988), Holy Family Parish in Novi (1988–1990), and Sacred Heart Parish in Auburn Hills (1990–1999). From 1988 to 1999, he was also the chaplain of Camp Sancta Maria, a Catholic boys' summer camp in Gaylord.
He sat on the Archdiocesan Presbyteral Council from 1990 to 1991, and on the Academic Concerns Committee of Madonna University's Board of Trustees from 1994 to 2000. From 1987 to 2000, he taught Church history and scripture at Sacred Heart Major Seminary in Detroit, of which he became Dean of Studies in 1990. Boyea was raised to the rank of Honorary Prelate of His Holiness on January 18, 2000. He was a weekend assistant at St. Mary Paris in German Village, Ohio (2001–2002) while concurrently serving as the Rector-President and a professor at the Pontifical College Josephinum in Columbus. A prolific author, he was also made editor of the North Central Association Self-Study Report in 1994, of the United States Catholic Conference Self-Study Report in 1995, of the Association of Theological Schools Self-Study Report in 1996, and of the National Conference of Catholic Bishops' Seminary Visitation Report in 1998.
On July 22, 2002, Boyea was appointed Auxiliary Bishop of Detroit and Titular Bishop of Siccenna by Pope John Paul II. He received his episcopal consecration on the following September 13 from Cardinal Adam Maida, with Archbishop Timothy P. Broglio and Bishop Thomas Joseph Tobin serving as co-consecrators. During his tenure as an auxiliary, Boyea served as Regional Bishop for the south region (2002–2003) and for the northeast region (2003–2008) of the archdiocese.
Pope Benedict XVI later named him the fifth Bishop of Lansing on February 27, 2008, after accepting the resignation of Carl Mengeling. Boyea, who was formally installed as Lansing's ordinary on April 29, is the spiritual leader of the 222,500 Catholics in the diocese.
Within the United States Conference of Catholic Bishops, he sits on the Committee on Clergy, Consecrated Life and Vocations, having formerly sat on the Committee on Boundaries of Dioceses and Provinces and on Priestly Formation and Committee on Selection of Bishops. The Bishop also belongs to the Catholic Biblical Association, Fellowship of Catholic Scholars, and American Catholic Historical Association.