After graduating from Harvard, Williams spent a few months at
Boston law firm
Ropes and Gray. After returning to New Zealand, he joined the law firm
Russell McVeagh McKenzie Bartleet & Co (now known as Russell McVeagh), where he took on two cases that went to international arbitration, the first such cases in New Zealand. He became a partner at Russell McVeagh in 1969, and at his suggestion, based on his experience in the United States, the firm introduced summer clerkships. Williams was a visiting scholar at the
University of Virginia Law School in 1979, and was also a part-time lecturer in law at the University of Auckland. He later served as president of the
Cook Islands Court of Appeal, and drafted the Cook Islands' Arbitration Act 2009. In the
2017 New Year Honours, Williams was appointed a
Knight Companion of the New Zealand Order of Merit, for services to international law and international arbitration. ==References==