This paper illuminates the role of activity theory in addressing theoretical and practical challenges raised by the growing role of digital technology in human activity. We explore and review the role of activity theory in the study of crucial digital technologies such as social media, smartphones, blockchain, artificial intelligence, and algorithmic decision-making, considering the unique ways that activity theory accommodates such technologies and can generate novel insights. We identify several apparent limitations of activity theory with an eye toward promoting its development and ability to incorporate modern perspectives and conditions. An important contribution of this paper is to stimulate future research that brings together activity theorists to study, in greater depth, the impacts of digital technology, and to help generate ideas on how it should shape future human activity. The themes covered are pressing questions not only for activity theorists, but for the ways we live, work, and play. We suggest activity theory can play a larger role in discourse on digital technologies, and their impact and evolution over time.