Mitochondria in osteoblasts have been demonstrated to play multiple crucial functions in bone formation from intracellular adenosine triphosphate production to extracellular secretion of mitochondrial components. The present review explores the current knowledge about mitochondrial biology in osteoblasts, including mitochondrial biogenesis, bioenergetics, oxidative stress generation, and dynamic changes in morphology. Special attention is given to recent findings, including mitochondrial donut formation in osteoblasts, which actively generates mitochondrial-derived vesicles (MDVs), followed by extracellular secretion of small mitochondria and MDVs. We also discuss the therapeutic effects of targeting osteoblast mitochondria, highlighting their potential applications in improving bone health. Mitochondria are known as the powerhouse of cells, producing energy to keep the cells functioning. However, recent discoveries show that mitochondria have more diverse roles. During bone formation, the cells responsible for building bones, called osteoblasts, rely on mitochondria for multiple important functions. This review explores the current understanding of how mitochondria operate in osteoblasts, covering their energy-producing activities, their role in generating oxidative stress, and how they change shape over time. The review also discusses the recent findings, such as the formation of unique structures called mitochondrial donuts and the discovery that mitochondria can be released outside the cells. The insights provided in this review suggest that targeting mitochondria in osteoblasts could be a promising strategy for improving bone health.