A native of Galveston, Sadie Gwin attended Rice University and became a permanent Houston resident shortly thereafter. An elementary school teacher by trade, she soon became a board member of organizations such as the Museum of Fine Arts, the Mental Health Association, River Oaks Garden Club, Bayou Bend Gardens, National Parks and Conservation Association, Junior League, and the Garden Club of America. She has published numerous articles, often in conjunction with renowned organizations such as World Wildlife Fund, Arnold Arboretum, and the Smithsonian Institute.