The aim of this article is to investigate the different types of il/legalities that Swiss immigration controls produce and their impact on the professional trajectories of highly skilled migrant men and women from South America. Although I will consider the issue of migrants having to validate their foreign educational credentials and professional experiences, my main interest lies in the valuing of degrees obtained in Swiss higher education (HE) institutions. In fact, reskilling in the sense of achieving post-obligatory education in the host country has been considered as improving the labour market participation of highly skilled migrants. However, I will focus here on the ways in which particular immigration controls such as the creation of categories of entry, the influencing of employment relations, and the institutionalisation of uncertainty (Anderson, 2010) mediate the employment conditions of highly skilled migrants with Swiss degrees. I will thus explore precariousness (Anderson, 2010) among highly skilled South American men and women working in gendered and foreign-based employment sectors such as care and academia. The Swiss migration regime creates il/ legalities according to the independent (student or worker) or dependent (family reunification) way of obtaining a residence permit. Drawing on a life course perspective, immigration controls reduce the value of Swiss degrees by reducing immigrants’ legal opportunities to work to a dependent legal situation or a no-permit situation. A hierarchy of professions, family caregiving norms and nationality stereotypes influences the assessing of their skills. These finding stress the interest of investigating skills as a relational concept that is constructed and valued by key actors in a transnational space in order to fashion highly skilled migrants as precarious workers.