Firmansyah heads the litigation division of KarimSyah Law Firm. He and his team have successfully argued hundreds of cases in the Indonesian courts, including some matters in which no other firm has as much experience, such as medical malpractice defense, aviation disaster resolution and enforcement of international arbitral awards.

Firmansyah obtained his legal degree from  Universitas Gadjah Mada Faculty of Law in Yogyakarta and a Master's from the University of Nottingham in the UK. Admitted to the Indonesian Bar in 1995, he is also licenced to practice by the Capital Market Authority, and is on the panel of arbitrators of several local arbitral institutions. Firmansyah was one of the drafters of Indonesia’s mediation regulation and teaches both litigation and mediation at the Faculty of Law of Universitas Gadjah Mada.

His major practice areas include not only dispute resolution but also banking & finance, capital market, general corporate, and mergers & acquisitions.