We investigated the development of narcissistic admiration (i.e., the assertive or extraverted dimension of narcissism; Back et al., 2013) and Machiavellianism (Mach) in early adulthood. Specifically, we examined (a) mean-level changes in narcissistic admiration and Mach during early adulthood and (b) how studying economics and experiencing any of 30 life events were related to individual differences in changes in narcissistic admiration and Mach. We used longitudinal data from 2 cohorts of young adults in Germany (N1 = 4,962 and N2 = 2,572). The mean levels of narcissistic admiration remained stable over time. Life events analyses indicated that narcissistic admiration increased among people who experienced a positively evaluated change in their eating or sleeping habits, a positively evaluated romantic break-up, or a negatively evaluated failure on an important exam. The mean levels of Mach decreased during early adulthood in both cohorts. Life events analyses showed that Mach decreased for only the 91% of young adults who had started a new job and evaluated it positively, suggesting that mastering occupational roles mitigates Mach in early adulthood. The results will be discussed in the light of previous longitudinal studies on narcissism and the Big Five and cross-sectional studies on how age is related to narcissism and Mach. (PsycINFO Database Record (c) 2019 APA, all rights reserved).