Abstract Introduction The International Study Group of Liver Surgery's criteria stratifies post‐hepatectomy liver failure (PHLF) into grades A, B, and C. The clinical significance of these grades has not been fully established. Methods The American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) hepatectomy‐targeted database was analyzed. Outcomes between patients without PHLF, with grade A PHLF, and grade B or C PHLF were compared. Univariate and multivariable logistic regression were performed. Results Six thousand two hundred seventy‐four adults undergoing elective major hepatectomy were included in the analysis. The incidence of grade A PHLF was 4.3% and grade B or C was 5.3%. Mortality was similar between patients without PHLF (1.2%) and with grade A PHLF (1.1%), but higher in those with grades B or C PHLF (25.4%). Overall morbidities rates were 19.3%, 41.7%, and 72.8% in patients without PHLF, with grade A PHLF, and with grade B or C PHLF, respectively ( p < 0.001). Grade A PHLF was associated with increased morbidity (grade A: odds ratios [OR] 2.7 [95% CI: 2.0−3.5]), unplanned reoperation (grade A: OR 3.4 [95% CI: 2.2−5.1]), nonoperative intervention (grade A: OR 2.6 [95% CI: 1.9−3.6]), length of stay (grade A: OR 3.1 [95% CI: 2.3−4.1]), and readmission (grade A: OR 1.8 [95% CI: 1.3−2.5]) compared to patients without PHLF. Conclusions Although mortality was similar between patients without PHLF and with grade A PHLF, other postoperative outcomes were notably inferior. Grade A PHLF is a clinically distinct entity with relevant associated postoperative morbidity.