A dynamic and hard-working offensive full-back, prior to joining Napoli in 2008, Maggio played for Italian clubs Vicenza, Fiorentina, Treviso, and Sampdoria.

Half of the registration rights were also sold to Parma in June 2002[4] for 4 billion lire (€2.066 million,[5] for an undisclosed cash plus Paolo Guastalvino).

[13] Maggio continued his good form as he scored the only goal of the game on 25 October, helping Napoli defeat Fiorentina at the Stadio Artemio Franchi.

As this raking pass came across his body from his left shoulder he volleyed it first time, with great power, swerving over the goalkeeper into the top corner.

During the 2011–12 season, his performances and attacking abilities continued to improve, as he netted three goals and provided five assists in 33 league games for Napoli.

[25] After missing out on a potential call-up for UEFA Euro 2008 under manager Roberto Donadoni,[26] Maggio was first called up to the national team by Marcello Lippi for the team's 2010 FIFA World Cup qualifying matches in October 2008,[27] but only made his debut with the Italy on 19 November 2008, at the age of 26, in a 1–1 friendly draw against Greece, coming on as a substitute for Mauro Camoranesi in the 61st minute.

[29] He took part at the 2010 World Cup;[30] although he was initially called up as the back-up for Gianluca Zambrotta, he played in the nation's third group stage match on 24 June, a 3–2 loss to Slovakia, coming on for Domenico Criscito at half-time; due to the defeat, Italy were eliminated in the first round of the tournament.

[31] After being briefly being excluded from the national side, he was called up by new head coach Cesare Prandelli on 6 February 2011 for a friendly match against Germany held in Dortmund,[32] and subsequently he became a regular for the team in the right back position under the manager; as a result, he was named to the 23-man Italy squad that took part at the UEFA Euro 2012.

[34] Maggio also appeared as a substitute in Italy's 4–2 penalty shootout victory over England in the quarterfinals, following a 0–0 draw after extra-time, playing as a right-back in a 4–3–1–2 after coming on for Ignazio Abate in the 90th minute; during the match, however, he received his second booking of the tournament, which ruled him out of the semi-final fixture against Germany.

[40] He once again started in the third-place match against Uruguay, where he helped the Italians to capture the bronze medal, following a 5–4 victory in the resulting penalty shoot-out after a 2–2 draw following extra-time.

[43] A dynamic, hard-working and tenacious right-footed player, with an eye for goal, for the majority of his career Maggio has been deployed as an attacking-minded full-back or wing-back on the right flank in a four-man back-line, although his preferred role is that of right-sided wide midfielder or winger in a 3–5–2 formation, a position which allows him both to make attacking runs up the wing, or late runs into the area, and also to track back, thus enabling him to cover the right side of the pitch effectively.

[44][45][46][47] Nicknamed "Super-bike",[48] due to his composure, pace, positioning, anticipation and stamina, he is capable of aiding his team both offensively and defensively.