Clinical benefit can be time-dependent even after first-pass recanalization (FPR) in endovascular treatment of acute stroke. This study aimed to evaluate the association between favorable outcome and FPR under a specific time frame. Patients who underwent mechanical thrombectomy were retrospectively reviewed. Recanalization status was categorized into four groups based on FPR and dichotomized time from groin puncture to recanalization (P-to-R time). Favorable outcomes were compared between groups. A total of 458 patients were included. As the cutoff of P-to-R time for favorable outcome was 30 min, recanalization status was categorized into FPR (+) with a P-to-R time ≤ 30 min (Group 1), FPR (–) with a P-to-R time ≤ 30 min (Group 2), FPR (+) with a P-to-R time > 30 min (Group 3), and FPR (–) with a P-to-R time > 30 min (Group 4). Favorable outcomes in Group 3 (37.5%) were significantly less frequent than those in Group 1 (60.4%, p = 0.029) and Group 2 (59.5%, p = 0.033) but were not significantly different from those in Group 4 (35.7%, p = 0.903). Compared to Group 1, Group 3 (adjusted odds ratio, 0.30 [95% confidence interval, 0.12–0.76]; p = 0.011) and Group 4 (0.25 [0.14–0.48]; p < 0.001) were adversely associated with favorable outcomes. FPR was associated with functional outcome in a time-dependent manner. Even for patients who have achieved FPR, their functional outcome might not be favorable if the P-to-R time is >30 min.