Having entered the provincial legislature, she was appointed the Member of the Executive Council (MEC) for Education, Arts and Culture.

The fourth out of six children,[1] Joemat-Pettersson was born as Tina Monica Joemat on 16 December 1963 in Kimberley in South Africa's former Cape Province.

She held a Bachelor of Arts in English and History as well as a Higher Diploma in Education from the University of the Western Cape.

[5] After the 2004 general elections, Dipuo Peters succeeded Dipico as premier and announced her executive council, in which she appointed Joemat-Pettersson as the MEC for Agriculture and Land Reform.

[8] In November 2012, Public Protector Thuli Madonsela found that Joemat-Pettersson had violated the Executive Ethics Code by unlawfully incurring return flights for her children and an au pair from Sweden to South Africa in January 2010.

Madonsela also found that she had violated the Ethics Code by staying at expensive hotels in Pretoria and Cape Town, which amounted to R900 795, while waiting for official residencies to be allocated to her.

[10] Zuma wrote to National Assembly Speaker Max Sisulu in March 2013, informing him that he had reprimanded Joemat-Pettersson for violating the Executive Ethics Code.

[11] In December 2013, Madonsela found Joemat-Pettersson guilty of maladministration for overseeing the irregular awarding of an R800 million-tender to Sekunjalo Marine Services Consortium to manage the Department of Agriculture, Forestry and Fisheries' fishery, research and patrol boats and trying to interfere in an investigation into the contract.

[12][13] Joemat-Pettersson unsuccessfully tried to challenge Madonsela's report on the matter, but her appeal was dismissed by the North Gauteng High Court on 13 March 2017.

[18] Public Protector Busisiwe Mkhwebane found in September 2020 that Joemat-Pettersson had no involvement in the sale and that she was misled by the then-head of the Strategic Fuel Fund Association, Sibusiso Gamede.

In October 2015, Earthlife Africa Johannesburg and the Southern African Faith Communities' Environment Institute (Saifcei) started a court case with both organisations challenging the national government's decision to procure nuclear energy without debating it in parliament first.

In April 2017, Western Cape High Court Judge Lee Bozalek ruled in favour of the two organisations' case, declaring that the government's efforts to acquire 9.6 GW of nuclear energy as well as Joemat-Pettersson's move for Eskom to procure nuclear energy as unlawful.

[25] On 7 April 2021, she became a member of the Committee for Section 194 Enquiry, which was established to determine whether Public Protector Busisiwe Mkhwebane should be removed from office or not.

[26] Joemat-Pettersson was elected chairperson of the African National Congress Women's League in the Northern Cape in 1998.

[14] Joemat-Pettersson died on 5 June 2023 at home in Rondebosch, Cape Town, as confirmed by ANC chief whip in Parliament Pemmy Majodina.

[39][40] Her death followed allegations of extortion in which she, Pemmy Majodina and Richard Dyantyi, the chairperson of Parliament's section 189 committee into the fitness of suspended Public Protector Busisiwe Mkhwebane were implicated.