It is now fashionable to seek innovation in the public sector. As routine government practices have failed to solve complex policy problems, innovation is increasingly seen as the key to establishing public faith in government agencies' ability to perform. However, not surprisingly, governments have often failed to support and maintain innovation over time. The purpose of this study is to examine what accounts for sustained innovation in government transparency. This is an in-depth analysis of the diffusion of the Electronic Freedom of Information Act (EFOIA) across the US states from 1996 to 2013. With the theoretical basis of policy diffusion, this study measures the degree of innovation among states by the timing of adoption, and by the extent of implementation. The factors that influence states' adoption and implementation of EFOIA will be compared, thereby explaining why some early adopters failed to maintain the leader position in innovation in government transparency through the implementation phase. The study findings show that the failure of early adopters in sustained innovation is the result of the conditional nature of diffusion mechanisms (i.e. socialization and learning) which operate differently at the adoption and implementation stages of EFOIA. This study contributes to a better understanding of the role of the legal environment created by the federal government, and the relationships between state governments in sustaining innovation in government transparency.