A problem with applications of innovations and technological tools such as the digital portfolio is that, while detailed conceptions and examples of digital portfolios exist, there is a chasm of practical advice that is sufficiently generic for guiding considerations on how to integrate digital portfolios into different learning environments. In this paper, it is argued that a powerful framework for guiding thinking about the integration of digital portfolios into teacher education is provided by cultural-historical activity theory or CHAT. CHAT is useful because it has been shown to provide a clear operational framework for the design of learning environments that support the integration of various technological tools.