Raynor Asher graduated BA, LLB (Hons) from the Auckland Law School in 1972. He was a Senior Scholar in Law. He was also the New Zealand Harkness Fellow to the United States in 1973-74 and graduated with a Masters of Laws from the University of California (Berkeley) in 1974.

Raynor was a partner at Kensington Haynes & White and Kensington Wallace, (later Kensington Swan) from 1976-86, and in 1986 commenced practice as a barrister sole.

In 1992, he took silk.

From 1996-98 he was President of the New Zealand Bar Association, and then President of the Auckland District Law Society between 2002 and 2003. He was Vice President of the New Zealand Law Society from 2003-05.

He was appointed to the High Court Bench in 2005 and to the Court of Appeal in 2016.

He has been President of the Legal Research Foundation, Chair of the Rules Committee and Chair of the Media and Courts Committee. He retired in March 2019, and resumed practice at the Bar as an arbitrator and mediator, and giving litigation and other advice. He is now Chair of the New Zealand Media Council, and a member of the Vanuatu and Cook Islands Courts of Appeal.

Raynor is a member of the Samoan and Pitcairn Islands Courts of Appeal.