Mark earned a PhD in economics from the University of Washington. He began his career as an economist for the Federal Trade Commission in Washington, DC, where his wife worked for Senator Slade Gorton and their children were born. But Mark refused to countenance living anywhere but the Pacific Northwest, where his pioneer ancestor Alfred Plummer helped found Port Townsend, so the family returned to live in Seattle, Vancouver, WA, and Federal Way. Mark relished meticulously planned expeditions to the region's ski resorts, golf courses, BBQ joints, fine restaurants, and, especially, wineries. He was also an early computer game enthusiast and beta tester. Mark lived life to the fullest and had few regrets, except perhaps the amount of Oregon pinot noir left to his wife.
Mark devoted his professional life to bringing the principles of economics into practical use. He brought intellectual energy, scientific rigor, and a sharp wit to this mission. His interests centered on the interactions of people and the natural world, beginning with his doctoral dissertation on California grape growers and wine labels (which, he would say, forced him to begin his wine collection). With his close friend Charles C. Mann, he co-authored two books, The Aspirin Wars and Noah's Choice: the Future of Endangered Species; the latter won the 1996 Washington Governor's Writers Award. He closed his career working for NOAA's Northwest Fisheries Science Center, in a job he described as "the best in the world, doing meaningful work for an agency with a meaningful mission." He developed a novel approach to evaluating the economics of designating critical habitat for salmon, for which he won a high profile agency award, in spite of (he noted) his penchant for wearing loud Hawaiian shirts. More recently he investigated the social and economic consequences of changes in natural ecosystems, such as the waters and resources of Puget Sound.