Mr Dias de Souza holds a bachelors degree in law from the University of São Paulo (USP) (1966). He is an expert in tax law and finance, and holds a Masters of Laws with a concentration in economic and financial law from USP.

He is a member of the Institute of Brazilian Lawyers (São Paulo and Federal District); the legal committee of the Federation of the Industries of the State of São Paulo; the São Paulo Academy of Law; the Brazilian Academy of Tax Law; the advisory council of the Brazilian Institute of Ethical Competition; a council member of the Lawyers Institute of São Paulo State (IASP); and a member of the Superior Council of Law at the Commerce Federation of São Paulo State (FECOMERCIO). Moreover, he is a former president of the International Academy of Law and Economy, and a former professor of tax law at USP.

Mr Dias de Souza was considered a leading lawyer in Chambers Global (2002-2019) and Chambers Latin America (2008-2018). He was also highly recommended by Practical Law Company (2008-2014) and named one of the most admired lawyers by Análise Advocacia (2006-2016). He was nominated by the Latin American Corporate Counsel Association as one of the best lawyers for tax in Latin America (2015-2016), and has been selected as one of the best lawyers in the tax category of both Best Lawyers: Brazil (since 2010) and Tax Expert Guide - Expert Listings: Latin America and the Caribbean (2015).

WWL says: Hamilton Dias de Souza is a "high-profile tax litigator" and "an excellent professional" who is known for his "reliable, diligent, punctual and timely" approach.