Ury has worked as a negotiation adviser and mediator in conflicts in the Middle East, the Balkans, the former Soviet Union, Indonesia, Yugoslavia, Chechnya, and Venezuela among other countries.
Ury founded and served as the director of the Harvard Nuclear Negotiation Project. In 1982, the United States Arms Control and Disarmament Agency requested that the Harvard Negotiation Project compile a report applying its understanding of human communication to the issue of superpower restraint in order to reduce the risk of a war started by accident, terrorism, mistake, runaway escalation, or misperception. Together with Richard Smoke, Ury interviewed U.S. and Soviet specialists and government officials, and published the report for the government in 1984. The report was the basis for Ury's book Beyond the Hotline. During this time, he also acted as a consultant to the Crisis Management Center at the White House, working to create Nuclear Risk Reduction Centers in Washington and Moscow, which were the subject of the first arms control agreement signed by President Ronald Reagan and General Secretary Mikhail Gorbachev.
Together with former President Jimmy Carter, Ury co-founded the International Negotiation Network, which worked to end civil wars around the world.The International Negotiation Network was led by a council that included Carter and Desmond Tutu. Other notable people involved with the Network include Javier Pérez de Cuéllar, Sonny Ramphal, and Sir Brian Urquhart.
Ury teaches negotiation to international corporate executives and labor leaders in order to reach mutually profitable agreements with customers, suppliers, unions and joint-venture partners.
In 2001, Ury co-founded the e-Parliament with Nicholas Dunlop. The website serves as a global forum for international elected officials to work on issues of common interest. The e-Parliament has given birth to the Climate Parliament, which links thousands of elected officials from 50 different countries to work together informally on issues of renewable energy and climate.