
From 1987 to 1991 and 1993 to 1996, he was a Tax Consultant at Coopers & Lybrand Auditores e Consultores.
He also worked for Mesbla’s Group and Xerox do Brasil, as tax
manager (1992 to 1993).
He worked at Ulhôa Canto, Rezende & Guerra Advogados (1996 to 2004) as tax lawyer and was one of the partners of Leoni Siqueira Advogados (2004/2008).
He was the founding partner of M. Guerra Advogados (2008) and afterwards of Guerra & Doin Advogados (since 2009).
He also was a professor of tax law at the Accounting and Business Administration Course at Faculdade Moraes Junior (IBRACON) and took part as Panelist in several seminars regarding tax legislation and federal contributions.
He was a Council member of the 1st. Trial Section of the Board of Tax Appeals (Conselho Administrativo de Recursos Fiscais – CARF). Currently he is an ABDF (Associação Brasileira de Direito Financeiro) member.
Co-Author of an article on e-commerce taxation published by the International Fiscal Association and co-author of the book “Legal issues of Petroleum and Natural Gas.”
He earned a Bachelor of Law degree from Universidade Federal Fluminense (UFF) and LL.M. degree in Contemporary Criminal Law at Fundação Getúlio Vargas (FGV-RJ).