Zofenoprilat, an angiotensin-converting enzyme (ACE; IC50 = 8 nM for rabbit lung enzyme) inhibitor and the active metabolite of the prodrug zofenopril, effectively counters angiotensin I- or bradykinin-induced contractions in isolated guinea pig ileum (EC50s = 3 and 1 nM, respectively). At a concentration of 10 nM, Zofenoprilat not only diminishes basal endothelin-1 secretion and nitric oxide (NO) production but also safeguards against TNF-α-stimulated increases in reactive oxygen species (ROS) and reductions in glutathione (GSH) levels within human umbilical vein endothelial cells (HUVECs). Furthermore, at 10 µM, it delivers protection to primary human cardiac microvascular endothelial cells from doxorubicin-induced toxicity and enhances hydrogen sulfide (H2S) production, along with the adhesion, migration, and proliferation of HUVECs. Additionally, Zofenoprilat (400 µM) mitigates end diastolic pressure and lactate dehydrogenase (LDH) release, demonstrating therapeutic potential in a Langendorff isolated perfused rat heart model of ischemia-reperfusion injury.