The majority of academic staff at universities and non-university research institutions in Germany today are employed on fixed-term contracts. This paper reconstructs the causes and dynamics of this development, which began in the 1970s, taking the example of the Max Planck Society (MPG) as a basis. While in 1976 just 15.7 percent of contracts were fixed-term, by 2016 that figure had risen to 69.2 percent. The motives of those at the top of the MPG, who gradually expanded the scope for fixed-term employment over the years, changed with time. In the 1970s and 1980s, fixed-term contracts were initially intended to help ensure mobility and to prevent overaging and an associated shortage of positions for early-career researchers. During the 1990s, however, strategic organizational interests gained increasing importance. Around the turn of the millennium, there was a strong belief that the MPG needed maximum flexibility in terms of human and institutional resources in order to compete globally with other research organizations for reputation and leadership personnel. The more research staff were employed only on fixed-term contracts, the easier it became to close obsolete departments and institutes, establish new ones in their place, and offer the newly appointed directors from around the world as many vacant positions as possible.