New concepts are continuously introduced in policies for science, technology and innovation (STI) across the globe, such as ‘transformative change’ or ‘responsible development’. Yet research has shown that ideas, even those that seem omnipresent in current policy for STI, like ‘innovation,’ come to be understood and are appropriated for distinct reasons in particular contexts. These varied understandings call for research that can uncover how global ideas come to be localized and the varied ways in which the local context informs global understandings in policy for STI. Shedding light on this paradox within policy for STI sits at the heart of this dissertation. One way to understand the development of global ideas within policy for STI over time is to consider the processes of isomorphism and difference-making that shape them. Not so they are put against each other in contention, but to understand how they work together and sustain each other over time. These dynamics capture the contextualization, multi-dimensionality, and emergence of policy for STI. The dissertation explores the ways in which global ideas are co-produced and how they are given life and made sense of within national policy for STI. I draw on insights from Science & Technology Studies (STS) and institutional theory to advance the conceptual lens of isomorphic difference. In doing so, I highlight the critical role of global ideas in shaping national policy for STI while underscoring the familiarity and distinctiveness at work within them. I draw on policy documents, interviews and participant observation to analyze particular global ideas in policy for STI within a national context and through cross-country comparisons. The first article departs from an exploration of the application of ‘diversity’ within the National Nanotechnology Initiative (NNI) in the United States. The next article takes on the ‘valley of death’ trope associated with commercialization efforts globally and traces the ways in which it gets interpreted and domesticated within the NNI. In the third article, I probe how policy instruments are mobilized dynamically to envision an innovation-based future in the United States and China. The fourth article emphasizes how the classic rationales (i.e., mission, curiosity and market) within strategies for STI in China, Denmark and the United States interact, feed into each other, and mutually shape one another over time. By tracing these global ideas across three national settings, new questions are raised about the relationship between STI and public policymaking—especially with regard to local strategies in the face of globalizing pressures and the entangled ways in which global ideas are co-constructed locally.