In order to better understand the factors fostering the success of school-to-work-transition (STWT), the current research examines a longitudinal model of proactive career development and career success on a sample of students transitioning from university to work. Using structural equation modeling, we tested a theoretical model based on Grant and Ashford’s (2008) and Hall’s et al. (2018) propositions, specifying the relationship between protean career orientation, career planning, networking behaviors and career success. A four-wave longitudinal study was conducted over three years on a sample of 231 university students (75% of female, mean age = 28.24 years) transitioning from school to work. The findings support the process model, indicating that protean career orientation influences career planning which in turn, positively affects networking. Finally, networking is found to be related to career success. The findings are considered in terms of their implications for understanding the process underlying the transition from school to work. Our study provides practical implications which are discussed.