As school-to-work transitions are highly institutionalised for young people in countries with well-established vocational education and training (VET) systems, comparatively smooth transitions to work and hence low youth unemployment have become the hallmark of VET. Tertiarisation, globalisation and increased macro-economic uncertainties as well as shifts towards a more knowledge-intensive economy and educational expansion, however, pose new challenges for VET. Based on data from the unique, longitudinal survey TREE (Transitions from Education to Employment) that follows school-to-work transitions of pupils who participated in PISA 2000, this dissertation sheds light on early job and employment insecurities and their lasting effects for the careers of VET graduates in Switzerland. Five research articles form the main pillars of this dissertation. Empirical results highlight the sheltering impact of vocational education on early job insecurity. In case VET graduates happen to experience early unemployment and initial fixed-term employment, however, they face long-term career hampering consequences. Further, institutionalised pathways to work along occupational lines constrain occupational mobility for VET graduates. Results indicate that graduates from initial vocational education strongly depend on good job opportunities in their occupational segment of training as they otherwise lack a pathway to qualified employment. In addition, the last empirical investigation focuses on differential effects of subjective and objective job insecurity on life-satisfaction trajectories across educational categories.