The movement was founded in July 1979 by Nigel Cantwell and Canon Moerman, the chair of the International Year of the Child, at a time when children's rights were not the main focus of many organizations.

The International Year of the Child instigated the dissemination of an unprecedented amount of information about children's rights violations such as torture, prostitution, economic exploitation, arbitrary detention, and trafficking and sale.

At the time, few international structures were dedicated to a human rights-based approach to the many problems faced by the world's children.  Defence for Children International was established in direct response to this gap.

Defence for Children mobilized the NGO community to become actively involved in the drafting process of the Convention on the Rights of the Child. The resulting NGO "Ad Hoc Group", established in mid-1983, made significant contributions to the Convention's final text.

In 1987, the NGO Ad Hoc Group joined UNICEF in publicly promoting the objective of having the Convention ready for adoption by the General Assembly of the United Nations in 1989.

Following the unanimous adoption of the Convention by the General Assembly on 20 November 1989, Defence for Children national sections successfully lobbied their governments to ratify the new Convention.

Defence for Children International sections were often the first to take the initiative of producing an NGO Alternative Report for the Committee on the Rights of Child, or to initiate national coalitions.

Through DCI's major role in co-ordinating NGO input to this drafting process, it developed substantial links with other NGOs and established itself as a centre of expertise and resources.