The diffusion literature is replete with examples of highly salient policies spreading across subnational governments. However, low‐salience policies that do not benefit from a groundswell of public opinion also spread across jurisdictions in patterns that appear similar to those of other, more well‐known policy ideas. This research is an investigation of the mechanisms that propagate low‐salience policies. I analyze the adoption of the U.S. Green Building Council's (USGBC) Leadership in Energy Efficient Design standard across 119 U.S. cities from 2000 to 2008. The investigation indicates that a knowledge broker, in this case the USGBC, occupies critical roles in linking a low‐salience policy to a broader set of widely held societal values, developing a common policy vocabulary, providing a base policy that jurisdictions may freely adapt, and creating a diffusion infrastructure by acting as a communication hub for existing and interested jurisdictions to discuss innovations and progress.