A naturally short sleeper phenotype with a sleep need of less than 6 hours without negative impact on health or performance is rare. We present a case of an acquired short sleeper phenotype after third ventriculostomy. A 59-year-old patient suffering from chronic hydrocephalus reported an average of 7-8 h of nocturnal sleep. After surgical intervention, the patient noted a strikingly reduced sleep need of 4-5 h without consequent fatigue or excessive daytime sleepiness, but with good daytime performance and well-balanced mood. Short sleep per 24 hours was confirmed by actigraphy. Postoperative imaging revealed decreased pressure around the anterior third ventricle. The temporal link between development of a short sleeper phenotype and third ventriculostomy is striking. This might suggest that individual short sleep need is not only determined by genetics but can be also be induced by external factors.