Romeo worked in the nunciatures in the Philippines, Belgium and Luxembourg and European Community, Venezuela, and Rwanda and Burundi.

At the same time, he worked as director of the "Casa Internazionale del Clero" and was regional assistant for the Lazio of the AGESC.

In 2005 Archbishop Romeo was awarded Knight Grand Cross of the Order of Merit of the Italian Republic.

He was created Cardinal-Priest of Santa Maria Odigitria at a consistory on 20 November 2010 and was eligible to vote in a papal conclave until his 80th birthday in 2018.

Cardinal Romeo is Sicilian Grand Prior of the Lieutenancy of the Equestrian Order of the Holy Sepulchre of Jerusalem.