The engineers' ethos can be explained by the composition of the population (mainly male, highly educated, at ease with science and coming from upper middle class families). But this ethos is also influenced by the graduates' secondary socialization in the engineering education and whilst at work. In this chapter, the author sets out to investigate the influence of the involvement of engineering students in a development-oriented association on their career path. The research is based on a large number of ex-members of the association "Engineers without Borders" in France. In this chapter, the author analyses by means of online CVs and interviews with ISF present-time staff current the professional path of a few main figures of the 30-year-old association.