Although he was a member of the squad during the 1972–73 season, Rossi made his debut in professional Italian football with Juventus in 1973, making an appearance in the Coppa Italia and winning a runners-up medal in the 1973 Intercontinental Cup. He was often injury-prone during his first few seasons, only making three Coppa Italia appearances with Juventus between 1972 and 1975, and scoring no goals. After three operations on his knees, he was later sent to gain experience with Como, where he made his Serie A debut during the 1975–76 season, initially playing as a right winger, where his small build would not be a hindrance; he made six Serie A appearances for the club, but again failed to score.

His career reached a turning point when Vicenza Calcio (then Lanerossi Vicenza) engaged him on loan. Coach Fabbri decided to move him from the wing and place him in the centre of the attack (because of injuries to the then centre-forward) just before the season started. Rossi immediately showed a tremendous knack for getting open in the box and scoring, winning the Serie B Golden Boot with 21 goals in his first year in this more advanced position. In the 1976–77 season, Rossi’s qualities as an implacable striker led his team to promotion to Serie A, and he also led Vicenza to the second group stage of the Coppa Italia that season. In the following season, Rossi scored 24 goals, to become the first player to top the scoring charts in Serie B and Serie A in consecutive seasons, also leading Vicenza to an incredible second-place finish in Serie A during the 1977–78 season, only behind co-owners Juventus. Due to his performances, he was selected by the Italian national team’s manager Enzo Bearzot for the 1978 FIFA World Cup. Rossi was also given his Italy debut under Bearzot on 21 December 1977, in a 1–0 friendly away win over Belgium.

Rossi confirmed his growth during the 1978 World Cup tournament, gaining international fame as one of the world’s best strikers. Playing for Italy as a central striker, he would sometimes switch positions with the two other forwards, going to his original right wing position. Right winger Franco Causio, a two-footed player, would go left, and Italy’s tall left winger Roberto Bettega would go to the center. This simple stratagem, made possible by the technical quality of all three players, created havoc in opposing defences, and Italy showed an entertaining offensive style of play in the tournament. Rossi totalled three goals and four assists as Italy finished in fourth place in that World Cup. He was named as part of the team of the tournament for his performances, and he also collected the Silver Ball as the second-best player of the World Cup. Rossi’s goal in Italy’s opening 2–1 group win of the tournament against France, on 2 June 1978, was also his first goal for Italy.

While at Perugia, he managed 13 goals in Serie A during the 1979–80 season, also helping the club to the round of 16 of the UEFA Cup. During the season, however, he was involved in the infamous 1980 betting scandal known in Italy as Totonero, and as a result of this Rossi was disqualified for three years, although this was later reduced to a two-year ban. As a result, Rossi missed out on the 1980 European Championship with Italy, where the team once again finished in fourth place, on home soil. Despite the ban, Rossi always claimed to be innocent, and stated that he had been a victim of an injustice.

Despite his ban, Rossi was repurchased by Juventus in 1981, and he returned to the starting line-up just in time for the end of the 1981–82 season to contribute to the club’s 1981–82 Serie A title (scoring one goal in three appearances), and to take part in the 1982 FIFA World Cup in Spain. Italian journalists and tifosi initially lamented that he was in very poor shape, however, and this view seemed to be confirmed by Italy’s appalling performance in the three group matches, in which he was allegedly described as a “ghost aimlessly wandering over the field”.

Italy manager Enzo Bearzot, however, staunchly confirmed Rossi for the decisive round robin in the second round, in which his team was to face Argentina, the reigning World Champions, and Brazil, the favourites to win the title with a team consisting of world-class players such as Sócrates, Zico, and Falcão. After Italy defeated Argentina 2–1, partly thanks to the defensive work of Claudio Gentile and Gaetano Scirea who shut down the young Argentine star Diego Maradona, Rossi scored three memorable goals to defeat Brazil 3–2 to qualify for the semi-finals. In the semi-final match against Poland, Rossi’s two goals won the match for Italy once again, granting them a place in the 1982 World Cup final. In the final against West Germany, Rossi scored the first of Italy’s three goals, from an indirect set-piece assist from Gentile, helping Italy win the match 3–1, giving his team their third World Cup title. With six goals in total, he won the tournament’s maximo goleador award, the Golden Boot, as the top scorer of the tournament, as well as the Golden Ball Award for the best player of the tournament, and he was named as part of the team of the tournament for the second consecutive time.

Italian fans hung banners proclaiming him “Man of the match”. Rossi’s accomplishments in Spain gained him the title of European Footballer of the Year and World Player of the Year in 1982, as well as the 1982 Onze d’Or Award. His goalscoring exploits during the tournament earned him the nicknames “Pablito” and the “torero”. Between his goals and assists throughout the tournament, Rossi was directly responsible for 58% of his team’s goals during the 1982 World Cup.

After the 1982 World Cup, Rossi continued to play with Juventus. During the 1982–83 season, Juventus finished second in Serie A, although he helped the club to win the 1983 Coppa Italia, scoring five goals. He also helped Juventus to reach the 1983 European Cup final, only to lose out to Hamburg; he finished the tournament as the top scorer, with six goals. During the 1983–84 season, Rossi won his second Scudetto title with the club, notably scoring 13 goals, also helping the club to win the 1983–84 UEFA Cup Winners’ Cup, followed by the 1984 UEFA Super Cup. During his final season with the club, Rossi finally won the European Cup in 1985, finishing the tournament with 5 goals, behind only teammate Michel Platini, and Torbjörn Nilsson, with 7 goals.

Rossi scored a total of 20 goals in 48 senior international caps for Italy. Undoubtedly, his most important goal was the winner against Brazil in the 1982 World Cup which completed a famous hat trick and enabled the Azzurri to advance to the semi-finals at the expense of the South Americans. Rossi further represented Italy in the 1991 edition of the World Cup of Masters, scoring in the third place play-off against Uruguay. Rossi is currently Italy’s joint all-time top goalscorer in the FIFA World Cup, with nine goals in 14 appearances over two editions of the tournament, alongside Roberto Baggio and Christian Vieri. Six of his World Cup goals came in seven appearances during Italy’s passage to triumph in 1982, and three of his goals came in seven appearances during the 1978 tournament, when Italy finished in fourth place.

After his stint with Juventus, he moved on to a then struggling Milan for a season in 1985. During his time with Milan, he was remembered for his two-goal performance against Internazionale in a Milan derby match. Rossi was also selected in Italy’s squad for the 1986 FIFA World Cup in Mexico, but did not play in the competition; an injury caused him to struggle during the team’s fitness tests, owing to the high altitude of the region. As a result, he was replaced by Giuseppe Galderisi up-front in the team’s starting line-up. He made his final appearance for Italy on 11 May 1986, in a 2–0 friendly home win over China in Naples. He ended his club career at Hellas Verona during the 1986–87 season, helping them to a fourth-place finish in Serie A, before retiring at the end of the season. He is currently involved in real estate, together with his former teammate Giancarlo Salvi.

In August 1990, he was named vice-president of Lega Pro Prima Divisione club A.S. Pescina Valle del Giovenco.

Pelé named Rossi as one of the top 125 greatest living footballers in March 2004; during the same year, Rossi placed 12th in the UEFA Golden Jubilee poll.