[2] At the age of 20, he entered the 1963 250cc Swedish motocross Grand Prix and scored an impressive second place finish behind the defending world champion, Torsten Hallman.
[2] After placing fourth in the 1967 250cc Swedish motocross Grand Prix, the Husqvarna factory gave Kring a motorcycle to compete with in the world championships.
[2] In 1967 Kring joined his Husqvarna teammates, Torsten Hallman and Åke Jonsson, along with ČZ factory teammates Joël Robert, Roger De Coster and Dave Bickers in a series of exhibition races in the United States that had been organized by Edison Dye, the American importer for Husqvarna motorcycles.
[10] Kring was having the most successful season of his career in 1970 when, he led in the 500cc world championship points standings with four overall victories in the first nine rounds before he broke his back while competing in a non-championship race.
[2][11] His injury ended his season however, he had accumulated enough points to claim second place in the world championship behind teammate Bengt Åberg.