[1][2] Denis Márquez Lebrón (born October 5, 1963) began his higher education journey at the University of Puerto Rico, Río Piedras Campus, after being admitted in 1981.

Along with his friend and fellow PIP advisor, José Torres Valentín, he entered private practice, specializing in labor law.

He has represented several labor unions and contributed to the legal representation of children with special needs in the Rosa Lydia Vélez class action lawsuit.

Denis has held several important positions within the PIP, including municipal legislator and president of the Gurabo Committee, Electoral Commissioner for Precinct 2 of San Juan, chair of the Evaluation Commission after the 2008 elections, and Secretary of Political Education.

His involvement in politics and activism began early, motivated by his first contact with the Puerto Rican Independence Party through his local community.