Abstract Introduction: While the efficacy of endovascular thrombectomy (EVT) in large core infarcts has been established, the influence of blood pressure (BP) management on functional outcomes based on infarct volume remains unclear. Patients and methods: We conducted a secondary analysis of the Outcome in Patients Treated With Intra-Arterial Thrombectomy–Optimal Blood Pressure Control (OPTIMAL-BP) trial, which compared intensive (systolic BP < 140 mmHg) versus conventional (systolic BP 140–180 mmHg) BP management within the first 24 h following successful recanalization. Patients were grouped based on an infarct volume cut-off of 50 ml, assessed 24 h post-EVT. The primary efficacy outcome was functional independence (modified Rankin Scale of 0–2) at 3 months. Change of predicted probability for functional independence between BP managements, as infarct volume varied, was assessed. Results: Of the 300 patients, 222 (74.0%) were in the infarct volume ⩽50 ml group and 78 (26.0%) were in the infarct volume >50 ml group. The conventional management was significantly associated with a higher rate of functional independence in the infarct volume ⩽50 ml group (adjusted odds ratio [AOR], 2.06 [95% CI, 1.12–3.86]). In the infarct volume >50 ml group, the proportion of patients with functional independence was not significantly different between BP managements (AOR, 1.52 [95% CI, 0.46–5.04]). The interaction effect between the infarct volume groups and BP managements was not significant. As infarct volume increased, the difference in predicted probability of functional independence between BP managements decreased. Discussion and conclusions: Conventional BP management showed greater benefits for achieving functional independence at 3 months when infarct volumes were smaller. As infarct volume increased, the impact of BP management strategies on functional outcomes decreased. Registration: ClinicalTrials.gov (NCT04205305)