Many young people experience episodes of unemployment and precarious employment such as insecure temporary jobs and skill-inadequate jobs during their school-to-work transition period. This essay summarizes key theoretical ideas and main previous empirical findings on the determinants and career consequences of having such a nonoptimal start into the working life. Then, this essay highlights cutting-edge research that has advanced our knowledge by providing more detailed insights into the individual-level career dynamics as well as the macro-level institutional and structural determinants of cross-country differences. This article concludes with a discussion of five key issues for future research. First, there is need for a better understanding of the institutional and structural influences on the career consequences of having a nonoptimal labor market entry. Second, the experiences during the economic crisis of 2008/2009 and its aftermath ask for a better understanding of why some countries performed better than other countries in protecting youths from that severe crisis. Third, a more detailed analysis of different forms of nonemployment and precarious employment is required in order to account for the strong variation of labor market experiences of youths. Fourth, to fully assess not only the risks but also the chances of taking up temporary jobs and skill-inadequate jobs at labor market entry, we have to complement the standard “upward comparison” to regular employment with a “downward comparison” to the alternative of nonemployment. Finally, this entry calls for an interdisciplinary and integrative approach analysing not only the work career consequences of bad labor market starts but also the social, economic, psychological, health, and familial consequences.