Mottley served as Finance Minister in the People's National Movement government between 1991 and 1995. He was responsible for the flotation of the Trinidad and Tobago dollar. He also won a silver medal and a bronze medal at the 1964 Summer Olympics in Tokyo.
He is currently a Senior Advisor and investment banker at Credit Suisse in New York. He was visiting fellow at the Center for Global Development, a United States-based think tank, where he researched and wrote "Industrial Policy in Trinidad and Tobago", a timely tome focussing on governance in an oil rich state.