Donald Simpson (1927–2018) was a neurosurgeon from Adelaide, Australia, who is often cited for the 1957 publication he wrote as a trainee on the relationship between extent of resection and outcomes for meningiomas. That paper summarized a series of over 300 patients operated on in England by well-known neurosurgeons Sir Hugh Cairns and Joseph Buford Pennybacker. Simpson was also known later in his career, when he was at the University of Adelaide in South Australia, for his contributions to the areas of hydrocephalus, spina bifida, craniofacial anomalies, head injury, brain abscesses, and neurosurgical history, and he published extensively on these topics. In addition to his work in clinical neurosurgery, Simpson made humanitarian contributions studying kuru in New Guinea and aiding refugees during the Vietnam War. Simpson was an active member and leader of many Australian surgical organizations and was an officer of the Order of Australia. Donald Simpson’s legacy as an adult and pediatric neurosurgeon, an academician, a leader, and a humanitarian is extensive and will prove long lasting. Professor Simpson’s life serves as an example from which all neurosurgeons may learn.