Khumalo was discovered while performing at a gospel talent search and signed a record deal with Bonsai Entertainment, released her début studio album, T.K.O (2005).

[4][5] Khumalo's ninth album, The Voice of Africa (2020),[6] which incorporated elements of R&B, gospel and Afro pop.

[16] In January 2018, Kelly began to work on her eighth studio album, and released its lead single "Jehovah" on 9 July 2018, featuring J F.L.O.

The song was certified gold by the Recording Industry of South Africa with sales of 80 000 units and garnered 12 million views on YouTube.

[22] "Esiphambaweni" featuring South African singer Hlengiwe Mhlaba, peaked number one in the gospel charts.

[23][24][25] At the 27th South African Music Awards, The Voice of Africa received a nomination as Best Afro-pop Album.

[29] In late August 2022, Kelly announced the From a God to a King tour, scheduled to start off on Saturday 17 September at Carnival City, Boksburg.

[38] On 26 October 2014, her boyfriend Senzo Meyiwa, former captain of the South Africa national football team and club side Orlando Pirates, with whom she has a child, was shot dead in her presence at her family's home in Vosloorus.

[45] She confessed to being a drug addict for at least two years during her relationship with the singer Molemo Maarohanye; she attended Narcotics Anonymous meetings.

[46] "Gospel Song Release - Esphambanweni featuring Dr Hlengiwe Mhlaba", AmenRadio, 12 Sept 2020.