Brynnie was trained as an international corporate lawyer , practiced law for many years assisting senior executives of US and European corporations with business and legal aspects of their operations in Latin America and Latin American and European investors with operations in the US.

She then e stablished management consulting firms both in the US A and Australia to assist management and staff to develop a values-based corporate vision and strategies for integrating the vision congruently into corporate planning and practices. She has founded the Cultural Diversity Program of the Conflict Resolution Network, a global organisation based in Sydney which provides facilitation, mediation and training materials on conflict resolution, and better access to services. and co-authored Valuing Diversity: Facilitating Cross Cultural Communication and Conflict Resolution and other related publications.

She also a ssisted in developing strategy and capital raising for the establishment of a listed biotech company in Australia . She also d eveloped successful capital raising strategy for building a new environmentally sustainable pre-school building in Sydney, Australia， as well as secured funding for the project .