Adapting or supplanting production and distribution systems to accommodate new criteria of environmental sustainability entails the search for and the recombination of know-how from a variety of domains. How this process plays out in different areas depends crucially on the specific composition of local economic activities. This paper contributes this debate by analysing whether and to what extent regional industrial and occupational diversification affects the change in green employment across 363 Metropolitan Statistical Areas (MSAs) in the United States between 2006 and 2014. Our findings suggest that industrial unrelated variety within MSAs is a positive and significant predictor of green employment growth whereas related variety has very little impact. Conversely, both related and unrelated diversification across occupations are positively associated with green employment growth. The analysis also uncovers heterogeneity across existing, new and evolving green jobs.