Mark Chapin Johnson is the founder and trustee of the Mark Chapin Johnson Trust, which develops, builds, and owns various small commercial and residential properties in the western United States. He began his career as founder, partner, and registered principal of Eastland Securities Corporation, a regional NASD firm specializing in small initial public offerings. Johnson also was founder, chairman, and CEO of Chapin Specialty Healthcare, a nationwide distributor of critical care and emergency pharmaceuticals to hospital pharmacies; in 2005 it merged with AmerisourceBergen, a Fortune 25 company.

Johnson is also the founder, chairman, and CEO of the Mark Chapin Johnson Foundation, a public benefit foundation active in various philanthropic activities. He is a board member of Boys Hope/Girls Hope and previously of the Pacific Symphony Orchestra. He is former chairman of the Institute for the Study of Media and Public Interest at the Dodge College of Media Arts at Chapman University, and he is a trustee of the World Affairs Council of Orange County. Johnson was also board chairman and CEO of the Orange County Performing Arts Center, chairman emeritus of the Southern California Entrepreneurship Academy, and board member of the YMCA of Orange County. He is currently a board member and overseer of the Hoover Institution at Stanford University.

Johnson received a PhD in Political Science from Claremont Graduate University in 2012, an MA in Politics from Claremont Graduate University in 2010, and a BA in Social Sciences from Chapman University in 2005. Currently he is a professor and trustee at Chapman University.

Johnson joined the Claremont Graduate University Board of Trustees in 2016.