Richardson was a lawyer by profession. She was elected as the Member of Parliament (MP) for Selwyn in 1981. Following the National Party victory in the , Richardson was appointed as Finance Minister in the fourth National Government. She supported and carried on the free-market reforms initiated by the preceding Labour Government, and extended them in a significant way with the Fiscal Responsibility Act 1994. Richardon's economic restructuring, including privatisation of state assets and cuts to social welfare, contributed to New Zealand emerging from its fiscal problems. However, critics have noted the wide-ranging effects on New Zealand's social fabric including child poverty along with wealth inequality, which were both severely exacerbated.