Abstract Background Stroke is an uncommon but significant complication of cardiac surgery. Cutibacterium (previously known as Propionibacterium) rarely causes infective endocarditis (IE), accounting for approximately 0.3% of all IE cases. Hyperbaric oxygen therapy (HBOT), involving the administration of 100% oxygen at a pressure of > 1.4 atmospheres absolute, increases the partial pressure of oxygen; therefore, it is recommended as an adjunctive treatment for stroke and some infections. However, there are no data supporting HBOT as an adjunctive therapeutic option for ischemic stroke related to post-cardiac surgery due to IE caused by Cutibacterium acnes. Case presentation: This study reports the case of an 68-year-old male patient who underwent cardiac surgery for native-valve IE caused by C. acnes. He underwent HBOT on postoperative day 11 for the treatment of ischemic stroke. The patient received 20 sessions of HBOT along with 6-week antimicrobial treatment with ceftriaxone and rehabilitation programs. Conclusions We have summarized the patient’s successful recovery and our clinical experience regarding the use of HBOT in our clinical setting. HBOT is an effective adjunctive therapeutic option for ischemic stroke related to post-cardiac surgery due to IE caused by C. acnes.