Grigg worked as a journalist for both Newstalk ZB and Radio New Zealand before shifting her career to politics.

[7] Grigg was selected as the National Party candidate for the Selwyn electorate in November 2019 on the first ballot, ahead of two other nominees: Simon Flood and Craig Watson.

[8] Following the election, Grigg served as National's spokesperson for women and, from August 2021, trade and export growth.

[7] In October 2023, Grigg revealed at a National Party press conference in Rolleston that she was six-and-a-half months’ pregnant.

While voting for the Contraception, Sterilisation, and Abortion (Safe Areas) Amendment Act 2022 during its first reading in Parliament, Grigg argued that establishing abortion safe zones would reduce "harassment, hate speech, and intimidation" by anti-abortion protesters against vulnerable women.