Using a longitudinal design, we asked 2 age cohorts of adolescents (15- and 18-year-olds) whether they, during the last year, had experienced events that had increased their civic interest and about details of their experiences. Based on self-determination theory, we predicted that the adolescents who reported having experienced events of this kind had already been more interested and had had more positive feelings about politics much earlier in time, and that this original interest would have increased more over time, than that of other adolescents. Second, we proposed that the adolescents who had encountered events that triggered their civic interest would have been engaged in behaviors that reflected their needs for autonomy, relatedness, and competence, much earlier in time, and that, over time, they would have increased these behaviors more than other adolescents. These 2 predictions were largely confirmed. As for the content of the events the adolescents reported, many of them concerned national and international issues experienced as threatening, and that challenged the adolescents’ beliefs and morality. Overall, a previous interest in politics and engagement in exploratory behaviors that reflect the adolescents’ psychological needs seem to play crucial roles in understanding why adolescents in their everyday life encounter events that trigger their civic interest. Further, the findings show that having had everyday experiences that trigger the adolescents’ civic interests are associated with a later increase in political interest more broadly.