[3] At international level, Santon made his senior debut with Italy in 2009, represented his nation at the FIFA Confederations Cup later that year, and earned 8 caps in total.
[16] In that match, manager Rafael Benítez preferred Iván Córdoba and Javier Zanetti in both full-back positions, as well as for the Champions League against Twente.
On 31 January 2011, the final day of the transfer window, Santon was sent out on loan to Cesena as part of the deal that saw Yuto Nagatomo join Inter in exchange.
He provided three assists to his teammates during the season: two against Chelsea for Jonás Gutiérrez and Moussa Sissoko,[24] and one against Wigan Athletic for Demba Ba,[25] as well as causing an own goal to be scored by Southampton's Jos Hooiveld.
[27] On 4 April, in the first leg of the Europa League quarter-final against Benfica, Santon's misplaced backpass allowed Lima to round Tim Krul and score from a tight angle.
[35] On 29 March, he made his return as a second-half substitute against Southampton, but allowed Rickie Lambert to get past him and score in an eventual 4–0 win for the Saints.
[40] In the 2014–15 season, a knee injury saw Santon miss much of Newcastle's campaign,[41] but by the end of the year, he had returned to the squad for a home match against Everton.
[44] After losing his first-team place to Paul Dummett, Santon returned to Inter in the 2015 January transfer window on loan, with an option to buy in the summer.
[51] However, Santon remained in Inter's squad, as they only had three available players eligible for the aforementioned quota in the Europa League (himself, Marco Andreolli and Jonathan Biabiany), with Serie A also imposing a similar homegrown rule.
The club was also forced to reduce the European squad to a maximum of 22 as a penalty for breaching UEFA Financial Fair Play Regulations.
[53] Santon was an unused substitute for Inter in the opening match of the Europa League; he was the starting full-back in their 2–1 win over defending Serie A champions Juventus in the Derby d'Italia.
On 31 March 2009, he made his debut for the under-21 squad in a friendly against the Netherlands, played at Parkstad Limburg Stadion, Kerkrade, which ended in a 1–1 draw.
[68] Santon made his debut with the senior Italian team at age 18, on 6 June 2009 in a friendly match against Northern Ireland, played in Pisa.
[70][71] Lippi was impressed enough to name him in the roster for the 2009 FIFA Confederations Cup,[72] but Santon did not manage to make an appearance in the tournament as Italy went out in the first round.
[73] After some strong performances since signing with Newcastle, Santon was recalled to the national team under manager Cesare Prandelli for the friendly against France in November 2012,[74] however he did not come off the bench in the 1–2 home defeat.
[76] Shortly after rejoining Inter Milan, Santon was recalled to the national team under manager Antonio Conte for the friendly against England in March 2015,[77] where he was an unused substitute.