Doxorubicin (DOX)-induced cardiotoxicity and sepsis-induced myocardial injury (SIMI) represent significant clinical challenges in patients undergoing chemotherapy, sharing a common pathological basis of oxidative stress and mitochondrial dysfunction. Ferroptosis, an iron-dependent form of regulated cell death driven by lipid peroxidation, has recently been shown to play a critical role in DOX-induced cardiotoxicity and lipopolysaccharide (LPS)-induced SIMI. This article systematically reviews the mechanisms underlying myocardial injury caused by DOX and sepsis, identifying ferroptosis as a central common pathway. DOX triggers a burst of reactive oxygen species within mitochondria and inhibits glutathione peroxidase 4 (GPX4) activity through redox cycling of its quinone group and high-affinity accumulation in mitochondrial cardiolipin. LPS, by activating pattern recognition receptors and related inflammatory signaling pathways, provokes a cytokine storm and mitochondrial dysfunction. Both can disrupt the core regulatory axis of cysteine-glutathione (GSH)-GPX4, synergistically promoting ferroptosis in cardiomyocytes. Moreover, epigenetic regulation plays a key role in DOX- and LPS-induced cardiomyocyte ferroptosis and may serve as a promising therapeutic target. A deeper understanding of the ferroptosis mechanism and its epigenetic regulatory network in the synergistic injury induced by DOX and sepsis is of great importance for developing novel strategies to mitigate chemotherapy-related cardiotoxicity and improve outcomes in cancer patients with concurrent infections.