[2] On 22 January 2008, Willemse released his debut single "Vertigo" exclusively on iTunes, through Mummy's Boy Records.

[3][4][5][non-primary source needed] The single's release also included two B-side tracks, "Shall Be Told" and "Home", each co-written by Willemse.

[9] During the super bootcamp stage of the competition, Willemse sang "I Gotta Feeling" by The Black Eyed Peas and "You Give Me Something" by James Morrison.

[9] For the first live performance show on 17 September 2012, Willemse sang Beyoncé's "Love on Top" and received praise from all four judges.

Mel B called the performance "incredible" and said that his voice is "bloody marvellous", while Ronan Keating added that he has a lot of soul.

In January 2013, Willemse embarked on the X Factor Live Tour with Samantha Jade, The Collective, Bella Ferraro, Shiane Hawke and Jason Owen.

[18] In Australia, it peaked at number four on the ARIA Singles Chart and was certified two times Platinum by the Australian Recording Industry Association for sales over 140,000 copies.

[22] On 24 January 2014, Willemse released a cover of "I Am Australian" with Dami Im, Jessica Mauboy, Justice Crew, Samantha Jade and Taylor Henderson, to coincide with the Australia Day celebrations.

[28] In November 2014, he was the supporting act for Mariah Carey's Australian leg of her tour, The Elusive Chanteuse Show.

[29] In December 2014, Willemse and other Australian singers recorded a cover version of Kate Bush's "This Woman's Work" under the name "Hope for Isla and Jude", and released it as a charity single to help raise funds for two siblings who suffer from the rare disease Sanfilippo syndrome.

In March 2016, it was speculated that Willemse had been dropped by record company Sony Music, along with other X Factor finalists Reigan Derry, Marlisa Punzalan and Dean Ray.

[36] On 11 January 2015, Willemse married his long-time girlfriend, model Fujan Erfanian on a tropical island in Langkawi, Malaysia.