Isolated, non-congenital herpes simplex virus type 1 (HSV-1) keratitis in immunocompetent infants is exceedingly rare and may be easily misdiagnosed, leading to delays in appropriate antiviral therapy. This case is unique in that it describes HSV-1 keratitis in a healthy 9-month-old infant presenting without systemic illness, initially treated as bacterial conjunctivitis. The patient presented with unilateral eye pain, redness, and corneal opacification. Subsequent evaluation revealed HSV-1 keratitis, and the patient was treated with intravenous acyclovir in combination with topical moxifloxacin and topical ganciclovir, resulting in complete resolution of symptoms within one week. This case adds to the limited literature on infantile HSV keratitis and highlights the importance of maintaining a high index of suspicion for HSV infection in infants with corneal involvement. Early recognition and prompt antiviral treatment are critical to preventing vision-threatening complications.