Photobiomodulation (PBM), also known as cold laser therapy, low-level laser therapy, laser bio-stimulation, red light therapy, and more, has been utilized in both animal and human models for over half a century. The modality is supported by thousands of research papers studying its effects on the repair, recovery, and performance of cells, tissues, and systems in mammalian physiology. In this chapter, we explore some of the available current research and discuss the mechanisms of PBM on the mitochondria through two current theories on how it affects both the electron transport chain and the interfacial water layers. Also discussed are PBM’s beneficial effects on the circulatory system, the lymphatic system, the immune system, the nervous system, and the muscular system. Transcription factors relating to the activation and proliferation of stem cells are mentioned as well. Included in the contents is information on PBM’s safety profile, differences between a laser diode and its LED cousins, and therefore special considerations when choosing and utilizing a PBM device. Also covered are the known contraindications for PBM use. The evidence in this chapter is directed toward clarifying PBM’s applications in repair, recovery, and restoration from the rigors of sport and exercise. Finally, recommendations regarding ways future research might be conducted to further assist with determining dose response ranges for its application and perhaps discover new types of applications in light of the current evidence.