Sir Peter Gross was born, and went to school, in Cape Town. He studied business sciences at the University of Cape Town and law at Oriel College, Oxford, where he was awarded the University's prestigious Eldon Law Scholarship. He was called to the Bar by Gray's Inn in 1977, and practised commercial law, latterly from 3 Essex Court (which later became 20 Essex Street). He was appointed Queen's Counsel in 1992, and as a Recorder in 1995. He also sat as a commercial arbitrator before he was made a Judge of the Queen's Bench Division in 2001. He was nominated to sit in the Commercial Court in 2002, and was Judge In Charge of the Court from 2009 to 2010. He also served as Presiding Judge on the South East Circuit and on the Special Immigration Appeals Commission. He was made a Lord Justice of Appeal in 2010, and, while in the Court of Appeal, also held posts as Deputy Senior and then Senior Presiding Judge for England & Wales, and as Lead Judge for International Relations.

Sir Peter retired in 2019, and resumed practice as an arbitrator. He enjoys outdoor pursuits, including sailing and cross-country skiing.