Mark J. Johnson received a bachelor's degree in art history from Brigham Young University in 1979. He went on to receive a master's degree in art history from the University of Illinois, Champaign-Urbana in 1983. He then attended Princeton University, where he received an MFA in art history in 1984 and a PhD in art history in 1986.
Johnson was a visiting assistant professor at University of Illinois, Champaign-Urban from 1986-1987. He then came to BYU and has taught art history since that time, both as a member of the Visual Arts Faculty and in the College of Humanities when the art history program was moved in 2015. He also served as the Visual Arts department chair from May 1997 through April 2003.
Johnson does research primarily in two periods: that known as Late Antiquity, encompassing late Roman, Early Christian, and early Byzantine art and architecture; and in the medieval period, more specifically, on the art and architecture of the eleventh and twelfth centuries in Norman, Italy. He is currently working on publications about the area. He has published on the architecture, mosaics, patronage, and literary sources of art of these periods. In 2003, BYU awarded him with the Alcuin Fellowship. Johnson published another book, The Byzanium Churches of Sardinia in April of 2013.
In 2006 he attended the 21st International Congress of Byzantime Studies at the University of London. In May of that same year Johnson and Latin professor Roger MacFarlane took a group of students to Naples, Italy, to study the architecture in Naples and the surrounding area. During the trip they also visited Pompeii to study Roman paintings. One house had just recently been excavated and showed evidence that painters were working on an interior wall the day Vesuvius erupted in AD 79.
In 2014, Johnson published a book entitled The Byzantine Churches of Sardinia. The same year, he received an Ancient Studies Professorship Award from BYU.