A lifelong South Bronx resident, Serrano was elected to the New York State Senate in November 2004. He defeated Republican Olga Mendez, a 26-year incumbent in the district. Since 2019, he has served as the Chair of the Majority Conference, the third highest-ranking member of the Senate.
He was the subject of Congressional campaign speculation when his father announced his retirement from representing NY-15, but chose not to run.[1]
In 2004, longtime state Senator Olga A. Méndez switched parties to become a Republican.[6] With the district overwhelmingly Democratic, Serrano was asked to run against her.[7] According to the New York Times, which endorsed him, Serrano promised "to pursue unfinished and ignored business in the capital, including legislating an end to the Rockefeller drug laws."[8] He would garner more than 80% of the vote in his victory over Mendez.[9]
Since his initial election to the Senate, Serrano has never faced serious opposition for general re-election.[10] In September 2007, he was named one of City Hall's "40 under 40" for being a young influential member of New York City politics.[11]
In 2019, Serrano was named Chairman of Committee on Cultural Affairs, Tourism, Parks and Recreation, a post he also held from 2009 to 2010.[12]
In 2020, he won reelection against Republican challenger Jose A. Colon with 82% of the vote.[13]