Background Temporal hollowing is inevitable after decompressive craniectomy. This complication affects self-perception and quality of life, and various techniques and materials have therefore been used to restore patients’ confidence. Autologous fat grafting in postoperative scar tissue has been considered challenging because of the hostile tissue environment. However, in this study, we demonstrate that autologous fat grafting can be a simple and safe treatment of choice, even for postoperative depressed temporal scar tissue. Methods Autologous fat grafting was performed in 13 patients from 2011 to 2016. Fat was harvested according to Coleman’s strategy, using a tumescent technique. Patient-reported outcomes were collected preoperatively and at 1-month and 1-year follow-ups. Photographs were taken at each visit. Results The thighs were the donor site in all cases for the first procedure. The median final volume of harvested fat was 29.4 mL (interquartile range [IQR], 24.0–32.8 mL). The median final volume of fat transferred into the temporal area was 4.9 mL on the right side (IQR, 2.5–7.1 mL) and 4.6 mL on the left side (IQR, 3.7–5.9 mL). There were no major complications. The patient-reported outcomes showed significantly improved self-perceptions at 1 month and at 1 year. Conclusions Despite concerns about the survival of grafted fat in scar tissue, we advise autologous fat grafting for patients with temporal hollowing resulting from a previous craniectomy.