Born in the United States, Rossi spent most of his career in Europe with Villarreal and Fiorentina, in addition to spells with other clubs in England, Italy and Spain, before returning to his country of birth to join Real Salt Lake for a single season in 2020.

Along with Mario Balotelli and Daniele De Rossi, he is Italy's all-time top scorer in the FIFA Confederations Cup, with two goals.

His father, Fernando Rossi from Fraine, Abruzzo, coached soccer and taught Italian and Spanish at Clifton High School.

His mother, Cleonilde Rossi from Acquaviva d'Isernia, Molise, was also a language teacher at Clifton, and his sister, Tina, currently lives in the United States.

[17] Rossi scored his only Newcastle goal in his first start on 25 October 2006, against Portsmouth in a League Cup third round tie at St James' Park.

[31] On 7 January, Fiorentina held a press conference unveiling Rossi, where it was revealed the player had signed a four-year contract containing a €35 million release clause.

[34] On 20 October, Rossi inspired Fiorentina to a 4–2 come from behind win over rivals Juventus, netting a 14-minute hat-trick that condemned Juve to their first defeat in Florence for 15 years.

[43] On 22 January 2016, Rossi returned to La Liga by signing a loan deal until end of the season with Levante, in order to gain playing time, and a place in the Italy national side at Euro 2016.

[45] On 13 March at the Estadi Ciutat de València, he scored the only goal of a win over city rivals Valencia CF, managed by his former United teammate Gary Neville.

[46] On 8 May, he scored a late winner in a 2–1 home win over title contenders Atlético Madrid, although the result was not sufficient to prevent the team from being relegated.

[51][52] On 9 April 2017, Rossi suffered the fifth serious injury of his career when he ruptured the ACL in his left knee in a game against SD Eibar, and was consequently ruled out of action for at least 6 months.

[53][54] Rossi became a free agent in July after Fiorentina allowed his contract to expire and he subsequently rejected an offer by Celta to remain with the Spanish side until January 2018.

[78] Italy national football team manager Marcello Lippi stated that had Rossi been fit, he would have received a call-up for the 2010 World Cup qualifiers in September 2008.

[81] Rossi scored his first goal for the Italy national team on 6 June 2009, in a friendly against Northern Ireland, at Pisa's Arena Garibaldi.

[86] On 17 November 2010, for his 18th cap for Italy, Rossi was picked by Italian manager Cesare Prandelli to wear the captain's armband for the first time ahead of the team's friendly against Romania.

[87] After a two-year absence from the national team due to injury, which saw him miss out on a place at Euro 2012, Rossi appeared in a 2014 World Cup qualifying match on 15 October 2013, as Italy drew 2–2 against Armenia at home.

[92] A quick and mobile left-footed forward, Rossi was known for his overall attacking and creative style of play, as well as his work-rate, movement off the ball, his powerful and accurate striking ability, and instincts in the box.

Regarded as one of the most promising Italian players of his generation in his youth, his playing style has often been compared to that of compatriot Alessandro Del Piero, due to his acceleration, strong technical skills, range of passing, dribbling talents, and his ability to either score goals or pick out a pass and create chances for teammates;[72][93] he was also compared to his namesake, 1982 World Cup-winning striker Paolo Rossi, due to his opportunism, pace, agility, and eye for goal.