Madlanga was born in 1962 in Njijini village, Mount Frere, to a family of the amaBhaca. He attended Mariazell High School in Matatiele. His father, a teacher, encouraged him to apply for a bursary to read law at the University of Transkei, where he completed a BJuris in 1981 in an atmosphere of growing unrest. During his final year he began working in a magistrate's office, though he was close friends with African National Congress activists under investigation by his colleagues. In 1985 he moved to Grahamstown, then in a state of "complete chaos", and completed an LLB at Rhodes University the following year. From 1987 to 1989 he worked as a law lecturer at the University of Transkei, teaching customary law, the law of delict and the law of contract. He won a scholarship to attend the University of Notre Dame and completed his LLM there in 1990. For the next six months he worked in the Washington, D.C. office of Amnesty International, where he briefly met Nelson Mandela after his release from prison.
On 1 August 2013, Madlanga was appointed permanently to the Constitutional Court, replacing Zak Yacoob. His appointment had been widely expected, especially after he impressed at his interview before the JSC, though some felt a woman ought to have been appointed. He was questioned on his 1998 judgment in Bangindawo v Head of the Nyanda Regional Authority, in which he had held controversially that there was "no reason whatsoever for the imposition of the western conception of the notions of judicial impartiality and independence in the African customary law setting". Madlanga admitted at the interview that this judgment was wrong. Madlanga's first judgment for the Constitutional Court was Gaertner v Minister of Finance, on the right to privacy and search and seizure. In March 2014, he wrote a 94-paragraph judgment dismissing Uruguayan businessman Gaston Savoi's challenge to his prosecution on charges of corruptly procuring a contract from the KwaZulu-Natal government. A year later, Madlanga delivered the controversial main judgment in Paulsen v SlipKnot Investments 777 Ltd, which removes an exception to the in duplum rule. This judgment was described as "consumer friendly", but marked a "sea change" for South African banking practice, and was strongly criticised extra-curially by Malcolm Wallis. Madlanga's next judgment for the Court was DE v RH, which abrogated the action for adultery. Madlanga was one of the authors of the majority judgment in the 2015 My Vote Counts v Speaker, National Assembly, which was widely condemned. The majority refused to hear an application by an NGO to compel Parliament to enact legislation requiring the disclosure of political parties' private funding.
Personal life
Madlanga's wife is Nkosisi Monica Madlanga. He has six children.