Arnold was born and educated in South Africa, then graduated as a vet in 1983 before joining Medivet in 1990.
Having practiced full time as a veterinary surgeon until 2002, as well as managing the business, Arnold then moved full time into management. These responsibilities included providing leadership for partnerships, acquisitions, joint ventures, finance, legal, IT, HR, construction, and design. He was co-leader until 2005.
Arnold held the position of Managing Partner and Head of Finance & Acquisitions until 2015, as well as Chief Executive Officer until October 2020. Now he acts as the Senior Partner and Advisor to Chairman and Board, supporting a range of activities.