The overarching aim of this dissertation is to expand evidence and theory of adult identity processes in the context of environmental stewardship, as well as to provide knowledge and recommendations to environmental stewardship and environmental education professionals. The intent is to better understand variation in how adult environmental stewards report on and value their own engagement with both sociocultural and natural systems. This line of inquiry stems from the fundamental claim that environmental stewardship activity is not singularly based on environmental content knowledge but is also related to forms of cultural and social engagement. By recognizing these dual aspects of environmental stewardship, organizers and educators can provide better support and resources for environmental stewardship efforts. This dissertation contains three manuscripts, two empirical and one conceptual work, that explore the sociocultural dimensions relevant to adult engagement in environmental stewardship. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]