Garrison received a Ph.D. in journalism from Southern Illinois University. He is the author of a series of journalism and mass communication books including Professional Feature Writing (2010), Online News and the Public (2004), Computer-Assisted Reporting (1998), Successful Strategies for Computer-Assisted Reporting (1996), Professional News Reporting (1992), Advanced Reporting: Skills for the Professional (1992), and Professional News Writing (1990). He also authored Sports Reporting (1993) and co-authored Latin American Journalism (1991), as well as numerous book chapters and journal articles. He serves on the editorial boards of Journalism & Mass Communication Quarterly and the Newspaper Research Journal.

Dr. Garrison also supervises the Our National Parks project (http://ournationalparks.us). He was a Research Fellow at Shanghai International Studies University in 2012 and he received a Fulbright Scholar grant and taught at Shanghai International Studies University in 2004-05. He continues to be an occasional guest lecturer at universities in China.