The government has sent its condolences to the family and friends of Professor Jakes Gerwel, who died on Wednesday morning.
"He played a significant role in shaping South Africa's political history through his involvement in the Black Consciousness Movement, led by Steve Biko," said Government Communication and Information System acting CEO Vusi Mona.
"Prof Gerwel will be sorely missed by government, academic circles, and South Africans at large," he said.
Gerwel (66) died at the Kuils River Hospital, in the Western Cape, on Wednesday morning.
The Nelson Mandela Centre of Memory, which Gerwel chaired, conveyed condolences on behalf of Mandela, the board of trustees and staff to the professor's family and friends on Wednesday.
"We will deeply miss 'Prof' as we fondly refer to him," the centre said.
"Our founder [former president Mandela] worked with Prof for many years, throughout his presidency and during and beyond his retirement.
"When Madiba stepped down in 1999 after serving one term as president of South Africa, Prof Gerwel, his director general, left the Office of the President to join Madiba in his post-presidential work."
Gerwel led the Nelson Mandela Foundation Board of Trustees and staff through its recent transition to the Nelson Mandela Centre of Memory, said its CEO Achmat Dangor.
"We will miss his wisdom and calm guidance," he said.
Gerwel was in a critical condition on Tuesday after undergoing heart surgery after incorrect posts on some media houses' Twitter feeds on Monday said he had died.
Family spokesperson Pam Barron said the family would like its privacy to be respected in the next few days and that funeral arrangements would be announced.
Gerwel was a well-known figure in South Africa's political history and in his later years he chaired and was on the board of major organisations and corporations.
Gerwel — an academic, executive and multi-award winner — served as director general in Mandela's office when he became the first democratically elected president.
He was born on 18 January 1946, in the Eastern Cape town of Somerset East.
He grew up on a sheep farm and later matriculated from Paterson High School, in Port Elizabeth, little knowing that one day he would become the right-hand man of South Africa's first democratic president.
In 1967, Gerwel graduated from the University of the Western Cape with a Bachelor of Arts degree and completed his Honours a year later.
In the late 1960s, Gerwel became involved in the Black Consciousness Movement. He became an educational adviser to the SA Students' Organisation (Saso) in the early 1970s.
For a short while, Gerwel lectured at the Hewat Teachers' Training College in Cape Town, and in 1971 he received a government scholarship to study at the University of Brussels.
There, he completed a licentiate [academic degree] in Germanic Philosophy and a literature doctorate.
When he returned to South Africa, he took up a teaching post at Grassy Park High School in Cape Town. He later moved to the University of the Western Cape and became a lecturer.
In 1980, Gerwel was appointed a professor and just two years later Dean of the Arts Faculty. He was appointed vice chancellor of the university five years later.
Gerwel's political participation against the apartheid regime raised university eyebrows and before his appointment to permanent staff he received three probations.
During the 1980 education protests, Gerwel was detained by the apartheid police.
Nine years later, he and Archbishop Emeritus Desmond Tutu, together with fellow teacher Franklin Sonn, were arrested during a march in Cape Town.
In 1991, Gerwel was elected as a member of the ANC's Western Cape regional committee.
On its website, the University of the Western Cape said Gerwel saw an "unambiguous alignment with the mass democratic movement and a new edge to the academic project".
It said that under the banner of "an intellectual home of the left", space was created for curriculum renewal and for innovative research and outreach projects.
"Important social and policy issues, which had been swept under the carpet by the government of the day, thus received attention," the university said.
It also formalised its "open" admissions policy, providing access to a growing number of African students.
In 1994, Gerwel was appointed to the post of director general in the office the Mandela presidency.
During his own time in the government, he named crime and unemployment as two areas of concern.
His awards include the Order of Southern Cross from Mandela, the Order of Good Deeds from Libya and Freedom of the Town from Somerset East.
He also served as chairman of Media24, the Allan Gray Orbis Foundation, and SA Airways, and was chancellor of Rhodes of University.
A rugby and cricket lover, Gerwel was the chairman of the policy committee of the 2003 Cricket World Cup.
He was married to Phoebe Abrahams and they had two children: a daughter, Jessie, a son, Heinrich, and four grandchildren.