There is only limited academic attention paid to the topic of Private Equity Investments in Family Businesses although the topic is becoming increasingly relevant for both entity types. In order to advance the field, this study focuses on the organizational metamorphosis of Family Businesses as a response to a Private Equity investment. In specific, changes in performance and its potential determinants were researched by means of eight case studies. The results indicate a neutral to beneficial performance development when Private Equity companies acquired a majority stake and a neutral development in case of a minority investment. Analyses further revealed that the positive performance improvement correlated with an organizational context that nurtured higher levels of individual discipline and stretch as well as organizational values that became aligned with market imperatives.