Carnosic acid (CA), a diterpene obtained mainly from Rosmarinus officinalis and Salvia officinalis, exerts antioxidant, anti-inflammatory, and anti-apoptotic effects in mammalian cells. At least in part, those benefits are associated with the ability that CA modulates mitochondrial physiology. CA attenuated bioenergetics collapse and redox impairments in the mitochondria obtained from brain cells exposed to several toxicants in both in vitro and in vivo experimental models. CA is a potent inducer of the major modulator of the redox biology in animal cells, the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2), which controls the expression of a myriad of genes whose products are involved with cytoprotection in different contexts. Moreover, CA upregulates signaling pathways related to the degradation of damaged mitochondria (mitophagy) and with the synthesis of these organelles (mitochondrial biogenesis). Thus, CA may be considered an agent that induces mitochondrial renewal, depending on the circumstances. In this review, we discuss about the mechanisms of action by which CA promotes mitochondrial protection in brain cells.