With more than twenty-three (23) years of experience as a lawyer, Cllr. Warner has extensive knowledge and practice in Liberian law. A member of the Cornell Law Journal while pursuing graduate studies, Cllr. Warner specializes in commercial, corporate and property law, and teaches legal writing, commercial law, and property law at the Louis Arthur Grimes School of Law, where he has been a member of faculty since 2008 and also did serve as Dean from 2016 to 2022.

Cllr. Warner holds law degrees from the Louis Arthur Grimes School of Law and Cornell Law School, and obtained admission to the Liberian Bar and the New York Bar in 2000 and 2003, respectively.

Some of the laws drafted by Cllr. Warner, which have in fact been enacted (and therefore in the public domain) include (1) the Act Establishing the Governance Commission; (2) The Act Establishing the Anti-Corruption Commission; (3) The Act Establishing the Liberia Extractive Industries Initiative; (4) the Liberia Freedom of Information Act; (5) The Act Establishing the Commercial Court of Liberia; (6) The Liberia Commercial Code, and (7) the Land Right Act of 2018, etc.

Cllr. Warner maintains a balanced interest and role in civil society activism, private legal practice, and public service, including extensive board experience. He currently serves as Chairman of the Board of Directors of Ecobank Liberia, Chairman of the Transparency International (TI) Chapter in Liberia- the Center for Accountability in Liberia (CENTAL), and a member of the Board of CSquared Liberia LLC. His previous directorships include service as Chairman of the Board of the Liberia Petroleum Refining Company, member of the Board of Access Bank Liberia Limited, Activa International Insurance Company (Liberia) Ltd, Diaconia Microfinance Deposit-taking institution , Open Society in West Africa (OSIWA), the international Board of the Extractive Industries Transparency Initiative (EITI).