Sebastián has been an associate at Arrubla Devis since 2018. Previously, he worked in the law firm Lloreda Camacho, in Bogotá, as director of Corporate Law. Moreover, he worked as an attorney for the office of the VP of legal affairs at the National Business Association ANDI (for its acronym in Spanish), where he represented Colombian businessmen in several technical subcommittees of the Commission for Dialogue on Labor and Wage Policies and was part of the Board of Directors of the Public Employment Service and the National Council of occupational hazards.

He has ample experience as a consultant for both national and foreign companies in the fields of contractual, corporate, and foreign exchange law, as well as corporate restructuring such as mergers, spinoffs, and liquidations, plus all litigious matters related to these fields. Additionally, he is a law professor at the Universidad Católica de Oriente and the Universidad Pontificia Bolivariana.