Bishop Alfred A. Schlert was born to Alfred and Marylou Schlert in Easton on July 24, 1961, and was educated at St. Jane Frances de Chantal Elementary School, Easton and Notre Dame High School, Easton. He prepared for the Priesthood at St. Charles Borromeo Seminary, Philadelphia, the Pontifical Roman Seminary, Rome and St. John Lateran University, Rome. He was ordained a priest at the Cathedral of Saint Catharine of Siena, Allentown on September 19, 1987 by The Most Reverend Thomas J. Welsh, Second Bishop of Allentown.
He served as a Parochial Vicar at St. Francis of Assisi Church, Allentown, as a Professor at his alma mater, Notre Dame High School, Easton and as the Catholic Chaplain at Lehigh University, Bethlehem. During his years at Notre Dame High School, he resided at St. Anthony of Padua Church, Easton, St. Bernard Church, Easton and Sacred Heart Church, Bath. He completed graduate studies at the Pontifical North American College, Rome and the Pontifical Lateran University, Rome where he received a Licentiate in Canon Law in 1992.
He was named Vice Chancellor and Secretary to Bishop Welsh in 1997 before being named Vicar General of the Diocese by The Most Reverend Edward P. Cullen, Third Bishop of Allentown, in 1998. As Vicar General, he oversaw the coordination of all administrative offices of the Diocese. From 1998 to 2008 he was in residence at the Cathedral of Saint Catharine of Siena, Allentown. While still serving as Vicar General, he was appointed Pastor of St. Theresa of the Child Jesus Church, Hellertown in July 2008. Upon the Ordination and Installation of The Most Reverend John O. Barres, Fourth Bishop of Allentown, he was reappointed as the Vicar General of the Diocese and resumed full-time service as Vicar General in February 2010, with residence at St. Theresa of the Child Jesus, Hellertown, until his Ordination as the Fifth Bishop of Allentown.
Pope St. John Paul II named him Chaplain to His Holiness with the title of Monsignor in 1999. Pope Benedict XVI named him a Prelate of Honor, the second highest rank of Monsignor, in 2005.
Bishop Schlert served as Vice President of the Pennsylvania Catholic Conference and as a member of its Administrative Board. He also served on the Diocesan Council of Priests, the Diocesan Finance Council and the Diocesan College of Consultors. He was a member of the Board of Trustees of DeSales University, Center Valley, Pennsylvania.
He was appointed the Fifth Bishop of Allentown by Pope Francis on June 27, 2017. He was ordained a Bishop and installed as the Fifth Bishop of Allentown on August 31, 2017.