Global Sydney is essentially a knowledge city. The global Sydney thesis has focused on Sydney’s performances in the knowledge-based economy, especially the advanced producer services, in an increasingly integrated world economy. Sydney’s emergence as a global city has been inseparable from its migrants from overseas and elsewhere in Australia. This study aims to bridge the theses of global Sydney and migration. The focus is on migrant knowledge workers employed in the knowledge-intensive industries and highly skilled occupations, which are the most reflective of Sydney’s knowledge capacity. Using data from the 2011 Australian Census and a community survey in the Sydney region, this study reveals new insights into the different patterns between international and internal migrant knowledge workers in terms of social–economic backgrounds, drivers for moving to Sydney, and employment before and in Sydney. The findings are useful to better understand migrant knowledge workers in global Sydney, and to contribute to the global city discourse and knowledge city research.