Hamizah holds a Bachelor of Law (Hons) from the International Islamic University of Malaysia. A qualified advocate and solicitor of the High Court of Malaya, she spent the early years of her career in legal practice. Hamizah holds a Company Secretary License issued by the Companies Commission of Malaysia (CCM) since December 1998 as well as the new Practising Certificate No.: 201908001071.

Hamizah joined TM as an Assistant Company Secretary in 1996 and promoted to Assistant General Manager in 2007. She was appointed as Joint Secretary on 15 July 2011 and thereafter as General Manager of Company Secretarial Unit of Group Legal, Compliance and Company Secretarial Division in 2012. She was named as the Group Company Secretary of TM effective 1 January 2017, heading the Group Company Secretarial Division of TM. Hamizah has more than 23 years corporate experience attending to company secretarial and compliance matters, governance matters, due diligence exercises and special projects.