Human Immunodeficiency Virus type-1 (HIV-1)-infected individuals show metabolic alterations of CD4 T cells through unclear mechanisms with undefined consequences. We analyzed the transcriptome of CD4 T cells from HIV-1 patients and revealed that elevated oxidative phosphorylation (OXPHOS) pathway is associated with poor outcomes. Inhibition of OXPHOS by the FDA-approved drug metformin, which targets mitochondrial respiratory chain complex I, suppresses HIV-1 replication in human CD4 T cells and humanized mice. In patients, HIV-1 peak viremia positively correlates with the expression of NLRX1, a mitochondrial innate immune receptor. Quantitative proteomics and metabolic analyses reveal that NLRX1 enhances OXPHOS and glycolysis during HIV-1-infection of CD4 T cells to promote viral replication. At the mechanistic level, HIV infection induces the association of NLRX1 with the mitochondrial protein, FASTKD5, to promote the expression of mitochondrial respiratory complex components. This study uncovers the OXPHOS pathway in CD4 T cells as a target for HIV-1 therapy.