Grover was originally a member of the National Party, but became disillusioned with National's economic policy under Minister of FinanceRuth Richardson. Richardson promoted strongfree marketeconomic theories, which were popular with some sections of the party, but resented by more conservative elements. Gilbert Myles and Hamish McIntyre, two National MPs who believed that Richardson's reforms were deeply harmful to society, split from the party in 1992, founding the new Liberal Party. Grover was one of those who accompanied them. Soon afterwards, the Liberals chose to join the Alliance, a broad left-wing coalition which they saw as the most significant opponent of Richardson and her allies. Some members of the Liberals, quite possibly including Grover, were unhappy at this decision, however — while they opposed Richardson's reforms, they did not see themselves as left-wing. Following the failure of either Myles or McIntyre to be re-elected, Myles decamped to the newly founded New Zealand First party and McIntyre retired. Grover assumed the leadership of the Liberals in 1994.
Member of Parliament
Grover was elected to Parliament in the 1996 election as an Alliance list MP. He disagreed with the Alliance on a number of issues, however, and on 11 June 1999, not long before the 1999 election, he officially quit the Alliance to join the Christian Heritage Party. This gave the CHP its only ever seat in Parliament. In 1998 Grover had indicated that he would stand for the Christian Democrat Party, but when they became Future New Zealand he decided to join the CHP instead. Grover's switches was strongly criticised by other parties, particularly the Alliance but also New Zealand First, which had also experienced defections. For the election, Grover was ranked sixth on Christian Heritage's list, but the party failed to win any seats. Grover therefore left Parliament. Before entering politics, Grover had a background in law, having received an LLB from University of Auckland. He worked as a magistrate in Hong Kong from 1979 to 1983.