Mary Gadams spends time between the United States, Scotland and Hong Kong. Her previous work experience is in investment banking and strategy. Shortly after the Asian financial crisis, Mary worked as a global strategist in the chairman's office and restructuring office of The Samsung Group in Seoul, Korea where she worked on special projects including mergers and acquisitions, joint ventures, venture capital and global strategy. Mary began her career in investment banking in the United States and left as a vice president to pursue language and graduate studies in Europe.

Mary is herself an ultramarathoner and endurance athlete having completed the Western States 100 Miler, the Atacama Crossing, the Marathon des Sables, the JFK 50 Miler, the Hong Kong Trailwalker, and many more ultramarathons and marathons, including the Boston Marathon (three times). Mary was also team captain of three Eco Challenge teams competing in Utah, Maine (as part of the ESPN X Games) and Borneo.

In the mid-90s, Mary saw a need for a global event series that captured the best aspects of all the events in which she had competed. Her vision was to create a series of events that would encourage people to push themselves beyond what they ever dreamt possible. In 2002, she created RacingThePlanet and the 4 Deserts Ultramarathon Series - a world-class footrace series taking place in the most challenging, pristine and culturally rich locations in the world. The four annual events would take place across the world's most varied terrain and would be located in the driest, windiest, hottest and coldest deserts on Earth. The races were named the Atacama Crossing (Chile), Gobi March (Mongolia), Namib Race (Namibia) and The Last Desert (Antarctica). The series has since been named by Time Magazine as one of the world's Top Ten Endurance Events, alongside such races as the Tour de France, Dakar Rally and Vendee Globe. In addition, there is a fifth event known as the RacingThePlanet Ultramarathon that moves to a new location each year.

RacingThePlanet has donated more than US$1 million to various charities as part of its events, with competitors raising millions more for charities of their choice. RacingThePlanet primarily supports education and healthcare initiatives in the areas where its races are held.

Mary is a non-executive board member of Montane and she and her husband currently own a macadamia and timber farm.