Maggio began his career at Vicenza making his Serie A debut in the 2000–2001 season, finishing the campaign with six appearances. However, despite some success on a personal level, Vicenza were subsequently relegated to Serie B at the end of the season. Maggio stayed with Vicenza until 2003, making 38 appearances in total while managing to score just 1 goal. Half of the registration rights were also sold to Parma in June 2002 for 4 billion lire (€2.066 million, for an undisclosed cash plus Paolo Guastalvino). In June 2003 the co-ownership deal was renewed.