NGM282, an engineered fibroblast growth factor 19 analogue, rapidly and significantly reduced liver fat content in a multicenter, randomized, double‐blind, placebo‐controlled study in patients with biopsy‐confirmed nonalcoholic steatohepatitis (NASH). However, it is unclear whether these changes would be accompanied by histological improvement. In this open‐label study, we assessed the histological efficacy of NGM282 in patients with biopsy‐confirmed nonalcoholic steatohepatitis. Paired liver biopsies from 43 patients who received subcutaneous NGM282 (1 mg, n = 24; 3 mg, n = 19) once daily for 12 weeks were evaluated blinded to time point, subject, and clinical information. At week 12, NGM282 significantly reduced nonalcoholic fatty liver disease activity score (NAS; −1.9; 95% confidence interval, −2.6 to −1.2; P < 0.001 in the 1 mg group; −2.2, −3.1 to −1.3; P < 0.001 in the 3 mg group) and fibrosis (−0.5; −0.9 to 0; P = 0.035 in the 3 mg group) scores. Overall, 50% and 63% of the patients receiving NGM282 1 mg or 3 mg, respectively, improved NAS by 2 or more points without fibrosis worsening. Of the patients receiving NGM282 1 mg or 3 mg, 25% and 42%, respectively, improved liver fibrosis by one stage or more without worsening of steatohepatitis. Treatment with NGM282 led to relative reductions in liver fat content (−58% and −67% in the 1 mg and 3 mg groups, respectively), corrected T1 (cT1; −8% and −9%), alanine aminotransferase (ALT) (−67% and −60%), aspartate aminotransferase (−57% and −52%), and fibrogenesis biomarkers neoepitope‐specific N‐terminal propeptide of type III collagen (Pro‐C3; −22% and −33%) and enhanced liver fibrosis score (ELF; −3% and −6%) at week 12. Greater reductions in Pro‐C3, ELF, and cT1, but not in liver fat content, 7alpha‐hydroxy‐4‐cholesten‐3‐one, or ALT, were observed in histological responders than in nonresponders. Conclusion: In this open‐label study, NGM282 improved the histological features of NASH in 12 weeks with significant reductions in NAS and fibrosis scores, accompanied by improvements in noninvasive imaging and serum markers.