McCardle originally worked for the New Zealand Employment Service, and was prompted to enter politics by a desire to make a significant contribution to unemployment and welfare policy.McCardle, however, found his party colleagues unwilling to adopt his radical employment policies, which were primarily based around the idea of "workfare".In 1996, after being involved in failed discussions with Mike Moore to form a new party, McCardle eventually decided to leave National and join New Zealand First, where he hoped to have greater influence.In the coalition government formed by National and New Zealand First, McCardle became Minister of Employment, and set about implementing some of his proposals.When the coalition began to collapse, McCardle joined the group that broke from New Zealand First to continue supporting the government.