Deng was born in what is now South Sudan. Her family became refugees in Kenya before moving to Melbourne, Australia at age 11 when the Australian government accepted them because her mother died of malaria. She has 7 siblings. Deng briefly quit modelling in 2016.
She auditioned for the role of a Bond girl but was told she was “too pretty” for it. Since 2018, she has been one of the faces of Fenty Beauty.