Immunothrombosis has emerged as a dominant pathological process exacerbating morbidity and mortality in acute- and long-COVID-19 infections. The hypercoagulable state is due in part to immune system dysregulation, inflammation and endothelial cell damage, as well as a reduction in defense systems. One defense mechanism in particular is glutathione (GSH), a ubiquitously found antioxidant. Evidence suggests that reduction in GSH increases viral replication, pro-inflammatory cytokine release, and thrombosis, as well as decreases macrophage-mediated fibrin removal. The collection of adverse effects as a result of GSH depletion in states like COVID-19 suggest that GSH depletion is a dominant mechanism of immunothrombosis cascade. We aim to review the current literature on the influence of GSH on COVID-19 immunothrombosis pathogenesis, as well as the beneficial effects of GSH as a novel therapeutic for acute- and long-COVID-19.