Born in Argentina to parents of Italian descent, Paletta represented his birth nation at the under-20 level, participating in the 2005 FIFA World Youth Championship in the Netherlands.
When Banfield qualified for the knockout stages of the Copa Libertadores, they altered their 25-man squad for the event to include Paletta and immediately threw him into action against the Colombian team Independiente Medellín.
[5] Paletta debuted for Liverpool in the 2006–07 Premier League season in a 4–0 away win against Wigan Athletic on 2 December; he was substituted onto the field for Sami Hyypiä in the 61st minute.
Paletta played a full 90 minutes of Liverpool's 2006–07 Football League Cup quarter-final match, a 6–3 home defeat against Arsenal on 9 January 2007.
On 26 August, it had been officially reported that Liverpool had agreed for Paletta to sign with Boca Juniors, having welcomed the arrival of Argentine Emiliano Insúa.
[9] Paletta played a full 90 minutes of Boca's 2007 FIFA Club World Cup 1–0 semi-final win against Étoile du Sahel on 12 December.
[11][12] During the 2008 Torneo de Verano, Paletta scored with header from a Jesús Dátolo free-kick in the 3–2 Copa Revancha loss against River Plate.
Paletta scored his first Copa Libertadores goal after nine minutes in Boca's last group stage fixture, a 3–0 home win against Maracaibo on 22 April.
[23] Paletta played a full 90 minutes of Boca Juniors 2009 Copa Sudamericana First Stage match, a 1–1 draw with Vélez Sársfield on 20 August.
[34] With the arrival of 11 new players in the summer transfer window, including central defenders Mateo Musacchio and Leonardo Bonucci, Paletta's opportunities at the club had been significantly limited.
[36] With Gattuso's appointment as a head coach of the senior team, Paletta got a rare opportunity to play full 90 minutes in an away Europa League 0–2 defeat against Rijeka once Milan had already qualified for the knockout stage.
[39] After being released by Jiangsu Suning, on 6 November 2019 Paletta signed a three-year contract for then-Serie C club Monza, owned by former AC Milan chairman Silvio Berlusconi and coached by his former teammate Cristian Brocchi.
He started in all seven games of the tournament, playing in the heart of the Argentine defence in a side also featuring future senior team stars Lionel Messi and Sergio Agüero.
In possession of an Italian passport due to his ancestry from Savelli in the province of Crotone, in Calabria, where his great-grandfather Vincenzo emigrated from,[42][43] Paletta is also eligible for the Italy national team.
[46] He made his competitive debut in the team's opening match, starting alongside Andrea Barzagli in central defence as the Azzurri beat England in Manaus.
He is good in possession and an attentive man-marker, although he is primarily known for his composure, aerial ability and heading accuracy; he has also drawn some criticism at times for being inconsistent, error-prone, and excessively aggressive when tackling, which led to unnecessary bookings and expulsions on numerous occasions.