Neonatal septicemia is the most common cause of death in neonatal foals. Actinobacillus equuli subsp. equuli is one of the most frequently isolated bacteria in septic foals, which leads to a syndrome colloquially known as “sleepy foal disease.” Congenital equine herpesvirus 1 (EHV-1) infection becomes evident within 14–18 hours after birth and foals often die within 24–72 hours. Previous studies have reported the association between A. equuli subsp. equuli and EHV-1; however, no clinical reports are present in the literature. This report describes the clinical presentation of A. equuli subsp. equuli septicemia secondary to EHV-1 congenital infection in a 6-hour-old foal. The foal developed a relative adrenal insufficiency, confirmed by hormonal concentrations. Adrenal gland ultrasonographic images were obtained, and the findings were coherently correlated with both macroscopic and histological postmortem evaluation.