Numerous studies have linked bureaucratic politicization – the appointment of bureaucrats based on political connections rather than merit – to greater corruption in government and worse public service delivery outcomes. Why does politicization have such effects? Prior studies have posited three main mechanisms. Politicization changes the incentives of bureaucrats, precludes socialization into an esprit de corps around public service, and selects less competent bureaucrats. We argue and provide evidence for a hitherto neglected mechanism: connection-based recruitment attracts and selects bureaucrats who are more dishonest and less pro-social. We test this argument with two behavioral games and original survey data from over 3,800 bureaucrats in Bangladesh, Ghana, Malawi, and Nepal. We find that bureaucrats who indicate that connections helped them get their jobs cheat more in honesty games and act less pro-socially in donation games. Our findings add an important empirical micro-foundation to studies of bureaucratic politicization and its behavioral implications inside government.