Sachs was born into a South African family of Lithuanian Jewish background. He attended the South African College School (SACS) in Cape Town. As a second year law student at the University of Cape Town, where he earned his LLB, he took part in the Defiance Campaign. Three years later, in 1955, he attended the Congress of the People at Kliptown, where the Freedom Charter was adopted.
Sachs started practice as an advocate at the Cape Bar aged 21, defending people charged under racial statutes and security laws under South African apartheid. After being arrested and placed in solitary confinement for over five months for his work in the freedom movement, Albie Sachs went into exile in England, where he completed a PhD from Sussex University, and later Mozambique. In 1988, in Maputo, Mozambique, he lost an arm and his sight in one eye when a bomb was placed in his car. After the bombing, he devoted himself to the preparations for a new democratic constitution for South Africa. He returned to South Africa and served as a member of the Constitutional Committee and the National Executive of the African National Congress, before seeking asylum in the United States.
Sachs was appointed to the Constitutional Court of South Africa by Nelson Mandela in 1994. His appointment was controversial, primarily because of his conduct at his JSC interview, where he was asked about his role in a report downplaying the ANC's indefinite detention and solitary confinement of Umkhonto we Sizwe commander Thami Zulu. One commissioner told Sachs his answers were "appalling" and criticised him for "sell[ing] his soul" by signing onto the report. One prominent lawyer later said that if Sachs's interview had been more widely publicised he "could not possibly have been on the Court". Sachs felt the criticism was unfair given his central role in ending torture in ANC camps.
Many of Sachs's best-known judgments are on discrimination law. He was the main author of the majority judgment in Prinsloo v Van der Linde, which established the connection between the right to equality and dignity. He was the author of the Court's majority judgment in Minister of Home Affairs v Fourie, in which the Court declared unconstitutional South Africa's statute defining marriage to be between one man and one woman. O'Regan J strongly criticised Sachs for referring the regulation of same-sex marriage to Parliament rather than providing immediate relief. The two had, in 2002, written a joint dissent which held that the criminalisation of sex work (and not its solicitation) unfairly discriminates on the basis of gender and is therefore unconstitutional.
Sachs retired in October 2009, along with Pius Langa, Yvonne Mokgoro and Kate O'Regan.
In 1991, Sachs won the Alan Paton Award for his book Soft Vengeance of a Freedom Fighter, which chronicles his response to the 1988 car bombing. He is also the author of Justice in South Africa (1974), The Jail Diary of Albie Sachs (1966), Sexism and the Law (1979), and The Free Diary of Albie Sachs (2004). His most recent book, The Strange Alchemy of Life and Law (2009), also won the Alan Paton Award, making him the second person to have won it twice. The Jail Diary of Albie Sachs was dramatized for the Royal Shakespeare Company by David Edgar, as well as for television and broadcast by the BBC in the late 1970s.
Sachs has 14 honorary degrees across four continents. In 2009 he received the Reconciliation Award as well as the Academy of Achievement Golden Plate Award. On 21 June 2014 he was awarded Taiwan's inaugural Tang Prize in the Rule of Law for his contributions to human rights and justice globally. In 2015 Sachs was named a Ford Foundation Art of Change Fellow. Sachs had helped select the art collection at Constitution Hill, the seat of the Constitutional Court.
Sachs has also served as a member of the Kenya Judges and Magistrates Vetting Board. He is currently an A.D. White Professor-at-Large at Cornell University.
In 1966 he married Stephanie Kemp, a member of the African Resistance Movement, ANC and SACP, in London. They had two children: Alan (an artist) and Michael (a developmental economist). In 1980 they divorced and Stephanie remained in London until 1990 working as a paediatric physiotherapist. He remarried in 2006 to urban architect Vanessa September in the Constitutional Court and they have a son, Oliver Lukutandu September Sachs.