Born in Johannesburg, Chaskalson was educated at Hilton College and later graduated from the University of the Witwatersrand with a BCom (1952) and LLB Cum Laude (1954).

[2] In 1963, Chaskalson, along with Bram Fischer, Joel Joffe, Harry Schwarz, George Bizos, Vernon Berrangé and Harold Hanson, was part of the former President Nelson Mandela's defence team in the Rivonia Trial, which saw Mandela sentenced to life imprisonment.

[7] He also wrote notable majority judgments in Soobramoney v Minister of Health, KwaZulu-Natal and Minister of Public Works v Kyalami Ridge Environmental Association, and he co-wrote Fedsure Life Assurance v Greater Johannesburg Transitional Metropolitan Council with Justices Richard Goldstone and Kate O'Regan.

In his 2005 State of the Nation speech shortly before Chaskalson's retirement, South African President Thabo Mbeki praised the Chief Justice as a "great son of our people" and a "giant among the architects of our democracy".

[9] In 2002 he was awarded the Order of the Baobab (Gold) for "exceptional service in law, constitutional jurisprudence and human rights".