Msimang was born in Zambia in 1974, where her South African freedom fighter father, Mavuso Msimang, had gone into exile, along with many other members of the then banned organisation the African National Congress. Her mother, Ntombi, was a Swazi accountant, and Sisonke grew up within the community in exile, along with sisters Mandla and Zeng.[1]
Msimang initially grew up around South African freedom fighters such as her father and great-uncle.[2] Her father was a leading member of uMkhonto we Sizwe (MK), the armed wing of the African National Congress (ANC), in the 1960s,[3] and her great uncle was one of the founding members of the ANC.The family later moved to Kenya and then to Canada in 1984 when Sisonke was 10.[4] Msimang completed most of her schooling in Ottawa, Canada, and her final years at the International School in Kenya as an expatriate.[5]
Msimang's first job was in 1997 as a programme officer at the Australian High Commission in Pretoria, which is where she met her husband Simon White.[5][7]
Msimang began her writing career in earnest from 2013, writing regular columns for the centre-right Daily Maverick.[12] In her first book, Always Another Country, she thanks editor Branko Brkic and CEO Styli Charalambous for 'giving me a start'.[5]
In 2017 Always Another Country: A memoir of exile and home was published in South Africa, with the Australian edition published the following year.[18][19][4] a memoir in which she describes her childhood and living in different countries, including what South Africa was like when she returned to it.[10] Written after the sudden death in 2014 of her beloved mother Ntombi, who had championed microfinance for female entrepreneurs in South Africa,[1] the book was highly praised by authors Tim Winton, Njabulo S. Ndebele and Alice Pung,[10] and earned accolades such the New York Times 2018 staff favourite of 2018 and CBC's Best International Non-fiction of 2018.[5] She writes in it about her upbringing among the ANC exiles: "Reft of a physical place in this world we can call home, exile makes us love the idea of South Africa. We are bottle-fed the dream: South Africa is not simply about non-racialism and equality but something much more profound".[1]
In 2014, Msimang moved to Perth, Western Australia, where she lives with her Australian husband, their two children and his children from a previous relationship.[1]