He is the author of over thirty books, including the bestselling Quicksilver Capital: How the Rapid Movement of Wealth Has Changed the World (with Dwight Lee). His most widely recognized and used book is The New World of Economics, which has between adopted in most of the country's major colleges and universities and has been translated into five foreign languages. Professor McKenzie's research covers many public policy areas but has been focused in recent years on the impact of global economic forces on businesses and governments, the safety effects of airline deregulation, and the impact of the growth in the elderly population on Social Security and Medicare.

Professor McKenzie has also written a memoir of his experience growing up in an orphanage in the 1950s, The Home, and on his recent experience living on the campus of The Crossnore School, Miracle Mountain, at the time a self-proclaimed “modern-day orphanage,” home and school for about a hundred children with multiple difficulties. He also authored Home Away from Home: The Forgotten History of Orphanage, edited Rethinking Orphanages for the 21st Century, and produced the documentary, Homecoming: The Forgotten World of America’s Orphanages, that aired on over 220 PBS stations.

Professor McKenzie has written a large number of monographs, chapters for larger works, and scholarly articles for a variety of academic journals. His columns and general interest articles have appeared frequently in most of the country's major publications and, including the Wall Street Journal, New York Times, Washington Post, USA Today, Washington Examiner, Christian Science Monitor, National Review and Forbes.