As a lightweight rower she was a national champion and won a silver medal at the 1990 World Rowing Championships.

Ninham was born in 1969 in the United States[1] and grew up in Cook, Australian Capital Territory with her three brothers.

[1] She is the fourth child of Professor Barry William Ninham the Head of Department - Applied Mathematics at the Institute of Advanced Studies of the Australian National University.

[12] The following year at the 1990 World Rowing Championships in Lake Barrington, Ninham held the three seat in the women's lightweight four which won the silver medal.

[8] An independent scholar and author affiliated with Melbourne's La Trobe University, her first published work was A Cohort of Pioneers, a study on Australia's growing intellectual, social, and research cultures since World War II.