Traumatic acute subdural hematoma (ASDH) is a medical emergency that requires prompt neurosurgical intervention. Urgent surgical evacuation may be performed with craniotomy (CO) and decompressive craniectomy (DC). However, a meta-analysis evaluating confounders, pooled functional outcomes, and mortality analyses at different time points has not been performed. A systematic search was conducted until August 28, 2023. We identified studies performing ASDH evacuation with CO or DC. Outcomes included Glasgow Coma Scale (GCS), Glasgow Outcome Scale (GOS), GOS-Extended, mortality, procedure-related complications, and reoperation. Variables were assessed using risk ratio (RR) and mean difference. Among 684 published articles, we included the Randomized Evaluation of Surgery with Craniectomy for Patients Undergoing Evacuation of ASDH (RESCUE-ASDH) trial, 4 propensity score-matched (PSM) cohorts, and 13 observational cohort studies. A total of 8886 patients underwent CO or DC. GCS at admission in unmatched cohorts was significantly worse in the DC group (mean difference = 2.20 [95% CI = 1.86-2.55], P < .00001). GOS-Extended scores were similar among CO and DC (RR = 1.10 [95% CI = 0.85-1.42], P = .49), including the RESCUE-ASDH trial. GOS at the last follow-up in unmatched cohorts significantly favored CO (RR = 1.66 [95% CI = 1.02-2.70], P = .04). Similarly, while short-term mortality favored CO over DC (RR = 0.69 [95% CI = 0.51-0.93], P = .02), both the RESCUE-ASDH trial and the PSM-cohorts yielded similar mortality rates among groups (P > .05). Mortality at the last follow-up in unmatched patients favored CO (RR = 0.60 [95% CI = 0.47-0.77], P < .0001). Procedure-related complications (RR = 0.74 [0.50-1.09], P = .12) and reoperation rates (RR = 0.74 [0.50-1.09], P = .12) were similar. Patients with ASDH undergoing DC across unmatched cohorts had a worse GCS at admission. Although ASDH mortality was lower in the CO group, these findings are derived from unmatched cohorts, potentially confounding previous analyses. Notably, population-matched studies, such as the RESCUE-ASDH trial and PSM cohorts, showed similar effectiveness in mortality and functional outcomes between CO and DC. Reoperation and complication rates were comparable among surgical approaches. Considering the prevalence of unmatched cohorts, our findings highlight the need of future clinical trials to validate the findings of the RESCUE-ASDH trial.