Since the early 1990s, Wallace has worked as a magazine writer and photographer, while producing long-form network news magazine programs on war, international organized crime, indigenous affairs, and the environment. From 1997 to 1999 Wallace worked for the Utica Observer Dispatch in Utica New York as a special projects, immigration and police reporter. The bulk of Wallace's work has been for the various entities of National Geographic, including National Geographic magazine, National Geographic Adventure, National Geographic Traveler, and the National Geographic Channel. His assignments for National Geographic have taken him from the rainforests of Brazil to the high mountain peaks of the Peruvian Andes and the rugged, windswept Wakhan Corridor in the western Himalayas of Afghanistan. Wallace specializes in the coverage of conflict over land and resources in remote locations, where crucial historical processes are unfolding beyond the sight of the rest of the world.