Arnold's appointment, effective Friday, will be presented to the Legislative Council for approval. He joins five other foreign judges from common law jurisdictions currently serving on the CFA. Hong Kong's Chief Justice Andrew Cheung welcomed the decision, which was based on a recommendation from the Judicial Officers Recommendation Commission.

Hong Kong leader John Lee stated that the presence of six overseas jurists demonstrates the independence of the judiciary and maintains strong links with other common law jurisdictions. He added that their participation signifies confidence in the HKSAR's judicial system.

Arnold, who has served on New Zealand's Supreme Court since 2013, retired from its permanent bench in 2017 but continues to sit as a retired judge. He previously held the position of Solicitor-General of New Zealand from 2000 to 2006.

The judiciary indicated that Arnold's appointment will offer greater flexibility in managing the court's caseload. This appointment occurs against a backdrop of several foreign judges leaving the CFA, with some citing concerns about the political environment and the role of overseas judges.