In 1998, Juventus decided to sign him; however, due to the presence of several more experienced and world-class midfielders ahead of him on the team, such as Antonio Conte, Didier Deschamps, Edgar Davids, Alessio Tacchinardi, and Zinedine Zidane, he struggled to gain playing time, and only made five league appearances for the Turin club, and 15 in total.

Despite his limited space at the club, he was able to score a goal in the Coppa Italia, make his Champions League debut, and appeared in the 1999 UEFA Intertoto Cup, which Juventus went on to win, before being sent out on loan to Bari.

[10] and then discounted to €7.05 million,[11] His first season at the club saw him play in a supporting role as a defensive midfielder, behind the attacking trio made up of Francesco Totti, Antonio Cassano, and Vincenzo Montella; however, the season was largely unsuccessful, as Roma underwent several managerial changes, suffered a first round elimination in the UEFA Champions League, finished eighth in Serie A, and lost out to Inter in the 2005 Coppa Italia final.

In merit of his fine performances for the capital club, he earned a call-up to Marcello Lippi's Italy squad for the 2006 FIFA World Cup, starting all seven games for the eventual champions.

He finished the season with 16 league appearances, only four as a starter, with two goals scored; under manager Aurelio Andreazzoli, he was left on the bench in Roma's 1–0 Coppa Italia final defeat to cross-city rivals Lazio.

[18] Perrotta was eligible to play for both Italy and England – the latter due to his birth in the country (in addition to being Italian, he is automatically a British citizen as the United Kingdom granted unconditional birthright citizenship until 1983).

[5] He won the 2000 UEFA European Under-21 Football Championship, appearing in Italy's 2–1 victory over the Czech Republic in the final,[5] but was later dropped from the 2000 Summer Olympics squad due to injury.

[29] In 2009, after being left out from 2010 FIFA World Cup squad by Marcello Lippi,[30] he retired from international football; he made his final appearance for Italy on 10 February 2009, in a 2–0 friendly defeat to Brazil, at the Emirates Stadium.

[32] A quick, physically strong, energetic, tenacious, and hard-working two-way player, Perrotta was known for his pace, versatility, and consistency, as well as his stamina, box-to-box play, and hard running style.

He was usually used in the centre, and often in a holding role in front of the defence, where he was adept at pressing opponents, breaking down plays, and subsequently distributing the ball to team-mates after winning back possession, or even linking up with other players through his passing to help start attacks.

[27][39][40][41] Under his Roma manager Luciano Spalletti, he was even fielded in a more advanced role during the 2006–07 season, as a false attacking midfielder behind the team's lone striker Francesco Totti in a 4–2–3–1 formation, the latter of whom acted as a false nine; this change of position was effective, due to Perrotta's movement off the ball, eye for goal from midfield, and ability to make late attacking runs into the penalty box, despite not being the most naturally technically gifted player in his position.

His parents, Francesco and Anna Maria, ran a pub in Ashton and lived on Fitzroy Street and briefly at the Chiltern Chapel before moving back to Italy in 1982, to their hometown Cerisano, near Cosenza.