In 1958 Clarkson qualified as a fitter and turner in Gisborne. He then moved to the Waikato and worked on the Kaimai Tunnel. He began selling and servicing tractors in Matamata before deciding to import V8 motors from the United States – a business he continued for nine years. Clarkson then moved into commercial building construction. Clarkson has played field hockey for the Poverty Bay provincial team. He was selected as a standby goalie for the New Zealand team that won Gold at the 1976 Summer Olympics. He was also a member of the New Zealand Stock Car Racing Team from 1968–1971, and held seven New Zealand titles in Dragster racing during 1972–1975. Clarkson was appointed a Companion of the New Zealand Order of Merit, for services to philanthropy, in the 2003 New Year Honours.
Member of Parliament
In the 2005 election, Clarkson was recruited as the National candidate for the Tauranga seat. He challenged Winston Peters, leader of the New Zealand First party, who had held the seat for twenty-one years. The contest was of national significance as party must have 5% of the vote or an electorate seat to qualify for proportional representation in parliament. A loss by Peters could have deprived New Zealand First of its electorate seat, leaving it vulnerable to a decline in its vote. Clarkson won the seat by 730 votes, a 2.02% majority over Winston Peters. However, New Zealand First retained representation by achieving 5.72% of the vote. As a member of parliament, Clarkson was the National Party's associate spokesperson for Building and Construction and Housing.
Controversies
Sexual harassment: "left testicle"
During the campaign sexual harassment allegations were made against Clarkson by a former employee. Clarkson claimed the allegations were the result of a misunderstanding arising from a mention of his left testicle to a colleague. It was claimed Clarkson repeatedly made jokes, such as "I bet my left testicle the all blacks will win" to female employees. Mr Clarkson, in the heat of the controversy, grabbed and talked about his crotch to a female reporter.
Campaign overspending petition
filed a petition in the High Court of New Zealand alleging that Clarkson had over-spent on campaigning than is allowed under the New Zealand Electoral Act. The Act prescribes a campaign spending limit of $20,000 per local candidate. Peters alleged that Clarkson had spent more than $100,000. However the High Court found that Clarkson had only spent $18,159. The court ordered Peters to pay $40,000 in legal costs to Bob Clarkson.
In several interviews, Clarkson has made a number of comments which caused offense to Muslim and homosexual groups. He was reported as saying that Muslim women wearing burqas, who did not want to fit in should "go back to Islam or Iraq" and that burqas should not be worn in banks or courts. Clarkson also made reference the number of gay and lesbianMembers of Parliament in the New Zealand Labour Party and was quoted as saying "We've got a problem there they are employing more of those than average people." The National Party MP caused further controversy after comparing homosexuality to nose picking saying that "If you walk up and down the streetpicking your nose, you're a bit different, aren't you? You're going to offend somebody." Clarkson was also reported as saying he had nothing against gays and lesbians unless they tried to "ram it down" his throat. While visiting a prominent all-male school in his electorate, he caused a negative reaction towards himself, and his party, by again referring to homosexuality as being "rammed down his throat". He also stated that "males needed to take back their rightful place as leaders" and made strong sexist comments towards an audience he expected would support him.
Mr Clarkson during a parliamentary debate on an electricity regulation to protect vulnerable customers yelled out "pay your bill" several times while the case of Folole Muliaga was being discussed. Mrs Muliaga died after her electricity was cut because she could not afford to pay the overdue bill. When asked to apologise in parliament after offence was taken by another member to the interjection, Mr Clarkson left the House after refusing to apologise. Clarkson said: "Sorry that's his problem." Mr Clarkson was reprimanded for the comments after John Key said the comments were "distasteful."
Stepping down from Parliament
In May 2008 it was announced Clarkson would not stand for re-election. He did not deliver a valedictory speech before he left Parliament on 25 September 2008. In 2011 he announced he was leaving the National party and joining ACT New Zealand, but he did not win any electorates after joining ACT, eventually leaving that party as well.