Mark Byrnes grew up in Murfreesboro and graduated from Riverdale High School before completing a B.S. in political science from MTSU in 1983. He went on to earn a Diploma in International and Comparative Politics from the London School of Economics (1987), and an M.A. and Ph.D. (1991) in political science from Vanderbilt University. A specialist in American government and politics, he joined the MTSU Department of Political Science in 1991 and has published books on NASA, James K. Polk, and Tennessee politics. Byrnes served as Dean of the College of Liberal Arts, which includes more than 300 full-time faculty members and nearly 60 full-time staff, from 2010 to 2016, and as Associate Dean of the College from 2006-2010.  He was confirmed by the MTSU Board of Trustees as University Provost in September 2017 following his appointment as interim University Provost in May 2016.

Byrnes was elected to two terms (2004-2012) on the Rutherford County Board of Education. During that time, he served as chairman for four years and vice chairman for three.

Byrnes has also served as president of the Tennessee Political Science Association and of the MTSU chapters of the American Association of University Professors and the Honor Society of Phi Kappa Phi.