This paper examines how the structure and content of individuals’ networks on the job affect intraorganizational mobility and work-related satisfaction. Consistent with prior research, we find that mobility is enhanced by having large, dense networks for those informal ties oriented toward acquiring information and resources. However, we argue that studies of networks and organizational careers have overlooked the importance of informal ties in transmitting social identity and normative expectations within organizations, which is facilitated by networks with the opposite features: smaller size and greater density or closure. We document this interaction between network structure and content in analyses of mobility and work satisfaction among 236 randomly-sampled exempt employees of a high technology firm. We also show how the effect of tie duration on mobility vary across types of network ties. The implications of these finds for theory and research on social networks and organizational mobility are discussed.