After school, she joined the New Zealand Women's Royal Army Corps (NZWRAC) for three years.
[2] Gardiner contested the Wellington Central electorate for National in the 1990 election against Fran Wilde, the incumbent of the Labour Party.
On election night, Gardiner had a lead, but Wilde won when the special votes had been counted.
[6] Like all United MPs but Peter Dunne, she was defeated in the 1996 election; she contested the Wellington Central electorate, where she came fourth.
[10] She is particularly critical of New Zealand's harm minimisation policy, which was introduced in 1990, and during this time, the country has become one of the highest users of drugs.