Interrupting parasite transmission from humans to mosquitoes is vital for malaria elimination and eradication. Plasmodium male and female gametocytes are the gatekeepers of human to mosquito transmission. Whilst dormant in the human host, their divergent roles during transmission become visually apparent soon after ingestion by the mosquito after rapid transformation into gametes – the males forming eight motile sperm-like cells that each aim to fertilise a single female gamete. Here we report that antibodies raised against PfLDH2 allow accurate identification of male gametocytes. Using this novel tool and functional mitochondrial labelling, we show that the male gametocyte mitochondrion is less active than that of female gametocytes. Rather than being a vestigial organelle discarded during male gametogenesis, we demonstrate that mitochondrial ATP synthesis is essential for male gametocytes to complete gametogenesis and inhibition leads to early arrest. Additionally, using a genetically encoded ratiometric sensor of ATP, we show that gametocytes can maintain cytoplasmic ATP homeostasis in the absence of mitochondrial respiration, indicating the essentiality of the gametocyte mitochondrion for transmission alone. Together, this reveals how gametocytes balance the conflicting energy demands of a dormant and active lifestyle and highlights the mitochondria as a rich source of transmission-blocking targets for future drug development.