Parés began his political career in 1983, when he was elected President of the PNP Youth of Precinct 4. Eventually, he became Municipal President of the PNP Youth in San Juan.
In 1992, Parés became part of the team of then-candidate to San Juan City Hall, Carlos Díaz Olivo. Parés was also one of Díaz' candidates to the Municipal Assembly of San Juan. Although Díaz Olivo wasn't elected, Parés became part of the Municipal Assembly after the 1992 general election. In 1993, he was appointed vice president of the body.
In 2002, he participated in a primary to fill a vacancy in the House of Representatives of Puerto Rico, representing District 4. However, he wasn't elected. Still, Parés became part of the team of then-candidate Liza Fernández, serving as her Campaign Director. After being elected, Fernández appointed Parés as Executive Director of her office, which he served until 2012.
For the 2008 general election, Mayor of San Juan Jorge Santini asked Parés to be part of his team of Municipal Legislators. With Santini's victory, Parés became a member of the Municipal Assembly of San Juan again.[2]
When Liza Fernández decided in 2011 to resign to her seat in the House to fill a vacancy in the Senate of Puerto Rico, Parés presented his candidacy for the seat. He was elected in the 2012 primaries. After being sworn in on May 24, 2012,[3] Parés became vice president of the Commission of Internal Affairs, as well as secretary of the Commission of Integrated Development of the Capital City, among others.