Sir Ross Cranston acquired degrees from the University of Queensland and Harvard Law School, and a doctorate from the University of Oxford. Called to the Bar by Gray's Inn in 1976, he combined practice in banking and financial services law from 3 Verulam Buildings with academic work, and held posts at the University of Warwick, the Australian National University, London University, and the London School of Economics. His teaching and research interests covered both banking and aspects of public law, and he published widely in both areas. He became a Recorder in 1997, and was appointed Queen's Counsel the following year. A member of the House of Commons from 1997 to 2005, he was Solicitor-General from 1998 to 2001. He became a Judge of the Queen's Bench Division in 2007, the same year in which he was elected a Fellow of the British Academy. He sat regularly in the Commercial Court from 2011. He also served as Judge In Charge of the Administrative Court from 2016 to 2017.

After retiring from the Bench in 2017, Sir Ross returned to legal academia, as Professor of Law at the London School of Economics, and to private practice as a commercial arbitrator.