Ivan Miller was born on 4 September 1949 in Blenheim, New Zealand, and went on to become one of the country’s most successful motocross riders of his generation. 

Miller began competing in motocross in 1964, at the age of 15. Just four years later, during the 1967/68 season, he won his first New Zealand championship titles, taking both the 250cc and 350cc classes.  His performances soon attracted attention across the Tasman. Miller made his first Australian appearance during the 1967/68 Australia–New Zealand International Motocross Series, beginning a long association with Australian racing and establishing himself as a regular international competitor.

In 1969, Miller travelled to England to pursue his racing career. He received valuable support from the renowned motorcycle dealership Comerfords, initially riding Bultacos before later switching to KTMs. Racing in Britain gave Miller the opportunity to compete against many of the world’s leading riders and further developed his reputation on the international motocross scene.

Miller returned to Australia in 1971 and enjoyed one of the most significant seasons of his career. Riding a Husqvarna, he won both the Australian 500cc and Unlimited Championships at Clarendon, South Australia. His success was particularly notable as he became the first international rider to win an Australian motocross championship. The Australian national championship was held immediately before the International Motocross Series, in which Miller also competed.

In 1972, Miller briefly broadened his racing career by riding speedway in Britain for the Rayleigh Rockets. Although he shared his first name with fellow New Zealander and world solo speedway champion Ivan Mauger, Miller’s principal passion remained motocross. Unlike Mauger, he did not go on to establish a major international speedway career.

Miller continued to make his mark in international motocross. In 1974 he finished third in the British 250cc Championship and on 20 October contested a round of the Trans AMA series in Gainesville, Georgia in the United States, riding a Penton.  The following year he was selected for the British teams competing in both the Motocross des Nations and the Trophée des Nations. The British teams finished third in both prestigious international events.