Robertson was a member of the North Shore Rowing Club. He won the first of his six Premier Redcoat National Rowing titles in the coxless pair with Mike Stanley in 1979. Perhaps his most impressive victory was three years later when he won the New Zealand nation championship in the 1982 men's single sculls title by defeating the five time national champion John Alexander from Whakatane as a Premier sculler at Lake Waihola. The following year in 1983 at Lake Horowhenia he won the historic and famed 'Boss Rooster' trophy in the coxed four with Mike Stanley, Rogar White-Parsons and Barrie Mabbott, and coxswain Andrew Hay. Later he was the three time consecutive national champion in the double sculls with Eric Verdonk in 1987, 1988, and 1989.