He attended Christchurch Boys' High School and has a BSc in Psychology from the University of Canterbury and then went to Canada for a Masters in Sociology at the University of Alberta. He studied towards but never completed a Ph.D in Sociology at the University of Toronto, before returning to New Zealand. Locke lectured in Sociology at Victoria University from 1970–72, but then decided to leave academia to work as a full-time editor of the fortnightly socialist paper, Socialist Action, from 1972 to 1976. From 1978 to 1984 he worked as an active socialist and unionist in a car factory, railway workshops and meatworks in the Wellington region. In 1985 he moved to Auckland, working in the Auckland City abattoirs, 1985–86. From 1986 to 1990 Locke worked full-time as the national coordinator of the Philippines Solidarity Network, based in Auckland. From 1990 to 1999 he was manager of One World Books, a non-profit bookshop in Auckland specialising in social, environmental and development issues.