Schnorrenberg is the son of Rudolph Hubert and Laura Schaeffer Schnorrenber. He completed primary school at Christ's School in Arden, North Carolina in 1949 and earned his bachelor's and master's degrees at the University of North Carolina in Chapel Hill. He taught a year at the Patterson School in Lenoir, North Carolina before enrolling in the Master of Fine Arts program at Princeton University. After earning his degree in 1957 he worked as an instructor at Columbia University and later joined the faculty at the University of North Carolina. He completed his Ph.D. at Princeton in 1964.
Schnorrenberg came to Birmingham in 1976 to teach art history at UAB and to chair the university's art department. Schnorrenberg's areas of expertise include medieval art and modern architecture, Gothic architecture, ancient Greek and Roman architecture and architecture in Alabama and the Southeastern United States. He curated a special exhibition of drawings by the architectural firm of Warren, Knight & Davis at the Birmingham Museum of Art in 1999.
Schnorrenberg is a member and former director of the Southeastern Society Architectural Historians and Southeastern Nineteenth Century Studies Association. He was president of the Southeastern College Art Conference for five years and also a member of the American Medieval Academy, the Society of Architectural Historians, and the American College Art Association.
He and his wife, fellow historian Barbara Brandon Schnorrenberg, married on July 7, 1962. They have two children, David and Katherine. After retiring from UAB in 2002, the Schnorrenbergs relocated to Alexandria, Virginia. He was widowed in 2013.
- Schnorrenberg, John M. (1999) Remembered Past, Discovered Future: The Alabama Architecture of Warren Knight & Davis, 1906-1961. Birmingham: Birmingham Museum of Art. ISBN 0931394430
- Schnorrenberg, John M. (2000) Aspiration: Birmingham's Historic House of Worship. Birmingham: Birmingham Historical Society ISBN 0943994268