Ackermann was born in Pretoria, South Africa and he matriculated from Pretoria Boys High School in 1950. He studied law at Stellenbosch and Oxford University, where he went in 1954 as a Cape Rhodes Scholar. Laurie served on the Lesotho Court of Appeal from 1988 to 1992 and as the Namibian Supreme Court's acting judge of appeal from 1991 to 1992. He is married to Denise and has three children.
Ackermann was appointed to the newly formed Constitutional Court in 1994 after his nomination by President Nelson Mandela.
He is an honorary fellow of Worcester College, Oxford, his old college.