Teachers are students' first contact in the classroom and the ones with whom they experience their relationships most intensely after those with their own classmates. Relationships with teachers and their actions in the classroom are of great relevance in how students develop their careers. Young people at risk of exclusion, which has been recurring in recent years, is an important matter. The aim with the research reported on here was to explore the life events and critical events that make it possible to describe the educational trajectory of young people at risk of exclusion who have dropped out of education and subsequently re-entered it. The aim was to investigate and characterise teacher-related events. We used a biographical-narrative approach by elaborating on the educational trajectories of young people at risk through the reconstruction of their life stories. Semi-structured, in-depth interviews were used to collect data. The main results indicate that the teachers' relationship with their students and the teaching methodology differ considerably in the different stages of their trajectory. Teachers in the reinstatement stage are more understanding of the different situations of students and are more supportive, leading to more positive events than in previous stages.