Sarah Walker after being elected to the commission. Photo: Getty Images
After initially being edged out for the fourth and final sport by Russian pole vaulter Yelena Isinbayeva, IOC president Thomas Bach proposed Walker also be elected.
The 2012 silver medallist will serve a term of eight years, through to the 2024 Olympics.
"It will be such a huge honours to be involved with the IOC and the Olympic Movemetn and I will be doing everything I can to represent all Olympics athletes as well as contribute my own perspective that I have gained through my Olympic journey," the New Zealand Herald quoted Walker as saying.
Walker missed qualification for the 2016 Games after an injury-plagued build-up.