Abstract In the last decades, young adulthood has established as an independent phase of life with important biographical transitions impacting further life course and health. In turn, health in adolescence can also affect the transitions into young adulthood. So far, for Germany there are no analyses on the association between family-related and employment-related biographies and obesity in young adults. The analysis is based on data from the KiGGS cohort study on 3,100 participants aged 23-31 at second follow-up (t2). Using BMI measurements at t0 (2003-2006) and at t2 (2014-2017), obesity groups were formed (no obesity, incidence, remission, persistence). Sequence analysis was used to retrospectively determine family-related and education/employment-related individual trajectories. Differences in life courses between obesity groups were calculated using discrepancy tests. Young adults with incident obesity were more likely to have children or to be a single parent than young adults without obesity at t2. Young adults with obesity at t0 lived longer in the parental home than those without obesity. Young adults with incident or persistent obesity were less likely to attend university and had experienced longer periods of unemployment than those without obesity at t0 and t2. The employment sequences of those without obesity at t2 were not statistically different. Both family and employment biographies were associated with obesity trajectories in young people. However, based on the analysis, it cannot be clarified whether early parenthood led to obesity or early transitions into parenthood led to interruptions in education or employment and subsequently to obesity. The finding that young adults with obesity were less likely to attend university and more likely to be unemployed could be related to disadvantages or discrimination in school, education or work. Obesity in adolescence that did not persist into young adulthood had less adverse effects on education and employment. Key messages Young people’s obesity trajectories were linked to different family/employment biographies. The life courses of young adults with obesity were more often marked by early parenthood and unemployment.