To meet ever expanding human needs, crops must become increasingly more productive, mainly through genetic gains that exploit diverse plant genetic resources, the raw materials for crop breeding. Plant genetic resources have been conserved by many different individuals and organizations, the stewards of our agricultural future. Their invaluable roles in underpinning the security of global agriculture have largely been underappreciated. Furthermore, the challenges and complexity of successful plant genetic resource stewardship have been inadequately recognized. This presentation pays tribute to these stewards’ contributions to plant genetic resource conservation, crop breeding, and research. It describes the pervasive impacts of plant genetic resources on crop agriculture and explains how numerous factors have affected plant genetic resource stewardship capacities. Plant genetic resource stewardship involves many different components, which are typically conducted over extended timeframes. Sustained, adequate support for plant genetic resource maintenance, a key component, has been the exception rather than the rule. Past and present plant genetic resource stewardship successes and challenges furnish numerous lessons for meeting future demands. Such lessons include recognizing the importance to plant genetic resource stewardship of: dedicated and diverse plant genetic resource stewards, continual and persistent financial support for plant genetic resource genebanks and their staffs, protecting crop wild relatives, and safeguarding genebank collections from extreme weather and introduced pests and pathogens. In the future, plant genetic resource stewardship might be conducted more frequently and more adequately by multi-institutional networks enabled by advances in information technology and artificial intelligence.