Raised within the Afrikaner volk, he became a fierce opponent of apartheid, contributing towards it demise through active lobbying, working towards development for all and the creation of democracy.
He also headed up the Urban Foundation and the Independent Development Trust (IDT), served on several commissions of enquiry, as Ombudsman for the Long-Term Insurance Industry and on the boards of non-profit organisations such as NICRO, and Communicare as well as companies such as Anglo American and Barclays Bank.
He was appointed as a Judge of the then Supreme Court of South Africa (Cape Provincial Division) at the young age of 36 in March 1964.
[4] His work beyond the confines of the law is described below under "Public interest bodies and boards of directors", but core to this was his involvement in the Urban Foundation and the Independent Development Trust.
After the Soweto uprising of 1976 Jan Steyn was instrumental in organising a summit of black urban leaders such as Nthato Motlana and industrialists led by Harry Oppenheimer and Anton Rupert.
In this way the Urban Foundation played a major role in improving the day-to-day lives of hundreds of thousands of disadvantaged South Africans.
"[4] The Urban Foundation successfully lobbied for the abolition of racially discriminatory enactments including the infamous pass laws, influx control and the Group Areas Act and invested large amounts of money in housing, education and associated developments, such as the electrification of Soweto.
[8] According to Jeremy Gauntlett, "[i]t grieved Steyn to see that a decade later, matric history textbooks claimed that the Urban Foundation and its successor [the IDT] had been an instrument to modernise racial domination.
"[4] When making his now famous address on 2 February 1990 the then State President of South Africa, FW de Klerk, when announcing the release of Nelson Mandela and the lifting of political restrictions, also announced the allocation of R2 billion for development to be administered by the Independent Development Trust (IDT) chaired by Jan Steyn.
[6] This initiative was launched after he obtained the unequivocal support of black leadership at the time, especially and including the late former president Nelson Mandela.
The IDT Board was led by people such as Mamphela Ramphele, Stanley Mokgoba, Harriet Ngubane, Wiseman Nkuhlu and Eric Molobi.
He served on the Board of Directors of Anglo American plc, Barloworld Limited, First National Bank, Metropolitan Life and Vergelegen and founded the Institute of Criminology at the University of Cape Town (UCT) in 1970.