This article discusses the role of soil microorganisms in the dynamics of soil organic matter (SOM) and how it is affected by land use and climate change. The authors highlight recent research that has shifted the understanding of SOM dynamics, emphasizing the importance of microbially derived SOM, microbial necromass, and root biomass and exudates. The article also presents five papers that investigate microbial control of SOM dynamics under different land uses and management practices. The findings suggest that microbial carbon use efficiency (CUE) is a key factor in balancing SOC accumulation and loss. The article concludes by emphasizing the need for a deeper understanding of microbial control of SOM dynamics in order to develop effective strategies for climate change adaptation and mitigation.