In 1998 Chadwick helped fellow kiwi Nathan Dahlberg setup the Marco Polo Cycling Team team. Glen Chadwick began his career in 2001 at the Belgian cycling team Landbouwkrediet-Colnago. In his first year, he came second in the general classification of the Tour de Liège. After two years he moved to Taiwan to ride for the Giant Asia Racing Team. Here he would win in his first year the Tour of Korea and the Tour of Beijing. In 2005 he rode for the Australian UCI Continental team Cyclingnews.com. After two years (2006, 2007) at the American UCI Professional Continental team Navigators Insurance he moved to Team Type 1 in 2008. During 2008 he won the Overall at the Vuelta Mexico Telmex. In 2009 he joined Rock Racing. Chadwick was part of the team sent to race the road race at the 2008 Summer Olympics.