Kris has been a legal academic in Auckland for close on two decades; prior to that he spent two decades in legal practice, mainly at the London bar. Mental health law, in both its civil and criminal aspects, has been a significant aspect of his work. He appeared in various precedent-setting cases in mental health law in England, edits the Mental Health Law Reports there and the International Journal of Mental Health and Capacity Law, was co-editor of New Zealand's Mental Health Act in Practice, and has written various articles and book chapters on mental health matters.