The 20-year-old narrowly lost the five-round Rotax Max Challenge but when the winner could not take the December prize trip to compete at the finals in Egypt, Booth was able to step up and claim it.
Auckland's Bradley Alexander nabbed the title by three points, despite Booth claiming victory in three rounds.
"I had two really bad rounds, which did cost me the series," Booth, a former Otago Boys High School pupil, said.
At the prizegiving function, Alexander explained that a pending back operation meant he was unable to compete in the international event, held in the city of Sharm el Sheik, on the southern tip of the Sinai Peninsula.
Booth received "quite a big shock" when the series organisers agreed to let him take the fully-funded opportunity instead.
Organiser Gavin Bright said it was the first time a Dunedin driver would attend the world finals in the decade the scholarship-style drive had been offered.
Booth and Tokoroa mechanic Bradley Tyrrell will have their airfares and accommodation paid for and have a kart engine and chassis provided.
It will be Booth's first overseas trip and the "biggest thing" for his career, he said.
Billed as the Olympic Games of karting, the event hosts 216 of the world's top karters from 57 countries.
Qualifying for the final will be a top priority as only about a third of the 96 Rotax Max heavy-class competitors will make it through.
Booth is hoping his performance attracts an international team's attention and would be "over the moon" with a top 10 placing.
Having won classes in the South Island kart championships in 1998, 2006 and 2007, he decided to concentrate on North Island-based Rotax series this year and has had his kart based up there with Tyrrell.
