The Yamaha ace - and current New Zealand MX2 champion - was unstoppable on the rolling grassland circuit, winning both races, finishing ahead of Spaniard Xevi Colomer Genis (Suzuki) and Sweden's Mats Nilsson (Yamaha).
Nilsson finished overall runner-up to King after his 3-2 results, and Colomer Genis (2-3) took the podium's third step.
"To win this championship is simply amazing," said King afterwards.
"The British Motocross Grand Prix track was one of the best tracks I have raced on.
"There were so many big jumps and bumps and ruts, and I have never experienced anything like it before.
"I felt totally in control and rode the bike better than I have in years.
"It was not an easy win, even though I rode as well as I did, because the second and third-placed riders finished really close behind.
"I really love riding dirt bikes and to win this World Championship shows that never giving up is the only way to go."
Other Kiwi world motocross champions from the past include Ben Townley from Taupo , who won the MX2 world championships in 2004, Aucklander Katherine Prumm, who won the women's World Cup in 2006 and 2007 and Pukekohe racer Tony Cooksley, who won the Veterans' World Championships in 2007.
Shayne King withdrew from top level motocross at the end of the 2007 domestic season but there's a stubborn, steely glint in the eyes of Darryll King when the subject of retirement comes up.
He's definitely not yet ready for the slippers, pipe and rocking chair option.
He plans to defend his national title in the coming summer months and intends heading back to Europe to defend his world championship next year as well.