[5] His first ever black-type win was Oopik ridden by then stable apprentice Peter Johnson in the 1973 Hawke's Bay Guineas.
[6] During his training career, O'Sullivan won one premiership title independently (1978–79 with 62 wins) and eleven in partnership with his son, Paul.
[7] In the 1992 Queen's Birthday Honours, he was appointed an Officer of the Order of the British Empire, for services to Thoroughbred racing.
[10][11] O'Sullivan's son Lance was a champion jockey who, like his father, was inducted into the New Zealand Racing Hall of Fame.
[12] Lance was appointed an Officer of the New Zealand Order of Merit, for services to Thoroughbred racing, in the 2003 New Year Honours.