Engineered living materials (ELMs) are composite technologies that respond to environmental cues, and are able to remodel, self-organise and self-heal. Proposed as a fusion of synthetic biology and classical materials science, ELMs are seen as having the potential to transform domains such as healthcare or transport infrastructure, and to underpin future circular bioeconomies. In this paper, drawing on work that explores the pragmatic dimensions of developing new biomaterials in collaboration with microorganisms themselves, we focus on how our interdisciplinary research team responded to the surprising behavior deployed by encapsulated bacteria in the biofactory system we designed. We suggest that—and describe how—this surprise prompted us to think like bacteria—to become bacteriocentric—and how this enables the deployment of this mode of practice in the building of ELMs. We propose that this alternation between surprise and control is essential to the technological development of ELMs, and to our interdisciplinary collaboration. We suggest that bacteriocentricity could be a powerful way to problematize and explore the role of bacteria in the making of sociotechnical worlds.