 That same year, at age 21, he returned to Puerto Rico and enrolled at the University of Puerto Rico Law School, becoming a licensed lawyer in 1956.Romero Barceló, an avid supporter of Puerto Rico statehood with the United States of America, became involved in with the "Partido Estadista Republicano", the forerunner of the New Progressive Party, which at the time was led by Miguel Angel Garcia Mendez.He formed part of "Ciudadanos pro Estado 51" (Citizens for the 51st State) in 1965.