This systematic review aimed to identify and describe best practice for the intraoperative anesthetic management of patients undergoing emergent/urgent decompressive craniotomy or craniectomy for any indication. The PubMed, Scopus, EMBASE, and Cochrane databases were searched for articles related to urgent/emergent craniotomy/craniectomy for intracranial hypertension or brain herniation. Only articles focusing on intraoperative anesthetic management were included; those investigating surgical or intensive care unit management were excluded. Nine studies meeting the inclusion criteria were identified after screening 1885 abstracts and full text review of 276 articles. Six of the 9 included studies were prospective and 3 were retrospective, and included sample sizes ranging between 48 and 373 patients. All were single center studies. Three studies examined anesthetic technique (volatile vs. intravenous), 1 examined osmotic diuresis, 1 examined extubation in the operating room, 1 examined quality metrics, and 3 examined intracranial pressure and changes in vital sign. There was insufficient evidence to perform a meta-analysis. Overall, there was limited evidence regarding the anesthetic management of patients having urgent/emergent craniotomy or craniectomy for intracranial hypertension or herniation due to any cause.