Previous research on reactivity—defined as changing organizational behaviour to better conform to the criteria of measurement in response to being measured—has found significant variation in company responses toward sustainability metrics. We propose that reactivity is driven by dialogue, motivation, and capacity in a configurational way. Empirically, we use fuzzy set qualitative comparative analysis to analyze company responses to the sustainability index FTSE4Good. We find evidence of complementary and substitute effects between motivation and capacity. Based on these effects, we develop a typology of reactivity to sustainability metrics, which also theorizes the use of metrics as tools for performance feedback and the building of calculative capacity. We show that when reactivity is studied configurationally, we can identify previously underacknowledged types of responses. We discuss the theoretical and practical implications for studying and using sustainability metrics as governance tools for responsible behaviour.