A descendant of South Florida pioneers, George began his career young, helping out with the family's native plant and tropical foliage nursery and with the family's restoration of a subtropical forest from an abandoned citrus grove. Between semesters at college, he worked as a resource management technician at Everglades National Park and traveled to the wilderness of Alaska; he also spent a semester abroad at the University of Costa Rica. In 1984, he earned a B.A. with distinction in Environmental Conservation and International Affairs from the University of Colorado. That same year he co-founded IRC, with whom he conducted a five-month study tour of the Brazilian Amazon in 1985. In 1986, he founded Ecohorizons, Inc., a private environmental consulting and contracting firm based in Miami, Florida, and from 1986 to 2010 he completed more than 250 projects comprising floristic inventories, rare species surveys, the preparation of management plans for public and private conservation areas, and the implementation of ecological restoration projects in both the public and private sectors. In 2010, he was named Director of Gemini Botanical Garden, a private 10-acre garden with major collections of Caribbean plants, which uses naturalistic design and ecological restoration principles to display its collections.

Following a decade of grassroots work on tropical forest conservation with IRC, George proposed the Floristic Inventory of South Florida (FISF) in 1994. In 1995 he became Executive Director of IRC and in 2004 it's President and Board Chair. Through 2012, he oversaw the completion of more than 100 conservation projects aimed at protecting and restoring rare species and ecosystems in South Florida and the West Indies. After 18 years as Executive Director of IRC, George stepped down from that position in 2013, assuming the newly created Chief Conservation Strategist position while remaing Board Chair.

George has personally conducted extensive field research and managed large multi-facetted research and conservation projects such as the FISF, Rare Plant Monitoring and Restoration on Long Pine Key (Everglades National Park), and Natives For Your Neighborhood, a web-based resource for native plant gardening and restoration in urban and suburban areas. Since 1987, he has published more than 100 articles, technical reports, websites, and the book Rare Plants of South Florida: Their History, Conservation, and Restoration (Gann, Bradley and Woodmansee 2002), which received numerous positive reviews from peers and in the journal Ecological Restoration. The FISF Database Online and other IRC online resources are widely used by academia, land managers, and botany enthusiasts.

George has given more than 100 presentations to both the general public and technical audiences at venues including Yale University, the University of East London, and Seoul National University (Republic of Korea). He has been active in several professional societies, including serving more than 25 years on the board of IRC, 17 years on the board of the Society for Ecological Restoration, including 4 years as Chair, an 11 year term on the board of the Tropical Audubon Society, and a 10 year term on the board of the Florida Native Plant Society. He has received several awards for his work, including Chair Emeritus from the Society for Ecological Restoration, the Conservation Colleague Award from The Nature Conservancy and the Board Appreciation Award from the Tropical Audubon Society.

While primarily focused on South Florida, George has significant international experience, embarking on his first professional expedition more than 40 years ago to the rain forests of Ecuador; he credits his parents, Donald and Joyce Gann, for his lifelong passion for plants. He has done significant organizational work in Europe and elsewhere for the Society for Ecological Restoration and botanical field work in more than a dozen Latin American and Caribbean countries. He is primarily self-trained and believes in developing and utilizing deep local knowledge to achieve conservation objectives and in forward thinking, not rear guard, conservation philosophies. As a founder of IRC, he embraces the idea that people and nature are not in inherent conflict, but that we must evolve to both improve human livelihoods and restore the bounty of the Earth, including its biological diversity. He lives in Delray Beach, Florida with his wife Egdomilia and their daughter Maya. His son Leif resides in North Carolina.