Zambrano & Gruba was originally organized in 1993. Its founders brought into the Firm vast experience and expertise in their respective fields of legal practice.

Atty. Daisy G. Zambrano (1948-2002) was a litigation practitioner for 26 years. She started as a legal researcher in the Court of Appeals before joining a Makati-based law firm as an associate lawyer. She had extensive work as a trial lawyer before civil, criminal and labor courts. She also appeared as counsel in arbitration cases involving the energy sector and constitutional law. Prior to her death, she was engaged in several complex litigation cases before the Court of Appeals and the Supreme Court involving constitutional issues.

Atty. Lily K. Gruba specializes in taxation, corporation law, banking and finance, energy law, infrastructure law and Build-Operate-Transfer (BOT) arrangements, investments law, mergers and acquisitions, and contract negotiations. Before co-founding the Firm, she worked with the Development Bank of the Philippines and later on became the General Counsel of the Landbank of the Philippines. From the banking sector, she moved on to government, where she worked as Undersecretary of the Department of Finance, in charge of Legal Affairs, Corporate Affairs,