Alisson began his career at Internacional, where he made over 100 appearances and won the Campeonato Gaúcho in each of his four seasons at the club. In 2016, he completed a €7.5 million transfer to Roma where he initially served as understudy to Wojciech Szczęsny before breaking into the starting line-up. In July 2018, Alisson signed for Liverpool for an initial fee of €62.5 million (£56m), which could rise to €72 million (£66.8 million); a world record fee for a goalkeeper at the time. In his first season at the club he received the Premier League Golden Glove for most clean sheets in the league (21), and kept another clean sheet as Liverpool won the 2019 UEFA Champions League Final.
The following year, Alisson found himself competing with Brazilian legend Dida, who had joined Internacional from Grêmio. He earned a starting berth in October and finished the year with 11 league appearances to his name. He was an undisputed starter in the following year during which he amassed 57 appearances across all competitions. On 4 February 2016, Alisson signed a pre-contract with Italian club Roma, signing a five-year deal for a €7.5 million fee. He played his last game for Internacional on 15 May 2016, keeping a clean sheet in a 0–0 home draw against Chapecoense. During his four years with Internacional's senior side, Alisson made over 100 appearances across all competitions and won the Campeonato Gaúcho title in each season.
Alisson officially completed his transfer to Italian Serie A side Roma in July 2016. He made his debut for the club on 17 August 2016, starting in a 1–1 UEFA Champions League draw with FC Porto, but spent the majority of the season as understudy to Polish internationalWojciech Szczęsny. He ultimately made 15 appearances across all competitions from the season but failed to feature in any league fixtures. Szczęsny departed at the start of the following campaign for Juventus, which saw Alisson assume the number one jersey. He later revealed that he would have considered leaving Roma had he not been guaranteed more first-team football.
Alisson made his official debut for Liverpool on 12 August, keeping a clean sheet in a 4–0 win over West Ham United. He received praise for his subsequent performances in wins over Crystal Palace and Brighton which saw him keep three consecutive clean sheets. In August 2018, Alisson was shortlisted for UEFA Champions League Goalkeeper of the Season, finishing in second place. On 1 September, in a 2–1 win over Leicester City, he received both praise and criticism for his performance, making several vital saves but also contributing to the opposition's goal. However, with Alisson in goal, Liverpool went on a run of 20 games unbeaten in the league from the start of the season which saw the Brazilian break Javier Mascherano's record for the longest-such streak. Alisson also played an important role in Liverpool's Champions League group stage campaign, making a vital save late on in their final group game against Napoli as Liverpool won 1–0 to advance to the knockout stages.
On 4 March 2019, he kept his 17th Premier League clean sheet for the season; the most by any Premier League goalkeeper in his debut season since former Liverpool goalkeeper, Pepe Reina in 2006. At the end of the season, Alisson kept a total of 21 clean sheets in Premier League, and won the Golden Glove. In the Champions League knockout stages, meanwhile, Alisson played a starring role as Liverpool advanced to their second consecutive final in the competition; in their second-leg semi-final at home to Barcelona, he made a number of impressive saves as Liverpool overturned a 3–0 first leg deficit to advance past their opponents with a 4–0 home win. In the final on 1 June 2019, Alisson kept a clean sheet for Liverpool as they defeated Tottenham Hotspur 2–0, making eight saves in the process, to win his first trophy with the club.
After spending his first season with the designated squad number 13, it was announced that Alisson would be wearing the number 1 shirt for the 2019–20 season, which had previously been occupied by Loris Karius.
Alisson started in the 2019 FA Community Shield against Manchester City on 4 August; after a 1–1 draw, Manchester City ultimately won the title 5–4 on penalties. On 9 August 2019, in the opening match of the 2019–20 Premier League season against newly promoted Norwich at Anfield, Alisson picked up a calf injury in the first half, and had to be replaced by new signing Adrián after 38 minutes. He was expected to be out injured for a "few weeks". As a result, he was ruled out of the 2019 UEFA Super Cup, which Liverpool won 5–4 on penalties on 14 August, following a 2–2 draw with Chelsea after extra-time. Alisson was said to be close to returning on 1 October 2019. He officially returned to the matchday squad on 20 October, in a 1–1 draw with rivals Manchester United. On 30 November, in a 2–1 win over Brighton, he was sent off for handling the ball outside his designated area.
On 5 May 2016, Alisson was named to Brazil's 23-man squad for the Copa América Centenario. In the team's first match, a goalless draw against Ecuador, he fumbled a Miller Bolaños shot into his own goal that was waved off because the ball had gone out of play beforehand. He conceded a total of two goals in three matches as Brazil were eliminated in the group stage.
In May 2019, he was included by manager Tite in Brazil's 23-man squad for the 2019 Copa América on home soil. Throughout the tournament, he only conceded one goal in six matches, as Brazil went on to win the title. The only match in which Alisson failed to keep a clean sheet was the 3–1 final victory against Peru on 7 July, at the Maracanã Stadium, in which he was beaten by a Paolo Guerrero penalty. Following the tournament, Alisson was honoured with the Best Goalkeeper Award for his performances.
Style of play
Alisson has been praised for his crucial saves, positioning, distribution and consistency, and is widely regarded as the best shot-stopper in the Premier League, and by some as one of the best goalkeepers in the world. Alisson cites former Barcelona goalkeeper Víctor Valdés as an inspiration, due to his ability to play out from the back, as well as Manuel Neuer, for his 'sweeper keeper' style. Alisson is also known for his speed and timing when rushing off his line, as well as his ability to clear or challenge for the ball with his feet outside the area; moreover, due to his distribution, he is capable of playing the ball out from the back quickly with his hands as well as his feet, and also has the ability to launch attacks, or pick out midfielders with his long goal kicks. His skills with the ball at his feet and composure in possession have even seen him take on opponents on occasion, when put under pressure.
Despite his height (standing at 1.91 m (6 ft 3 in)), strength, size, and his large, powerful physique, he is also an agile and athletic goalkeeper. Alisson possesses good reflexes and excellent shot-stopping abilities, as well as the capacity to produce spectacular and instinctive reaction saves when necessary, which earned him the nickname O Goleiro Gato ("The Cat-like Goalkeeper," in Portuguese) in the Brazilian media, but he is predominantly known for his efficient style of goalkeeping, courtesy of his anticipation, consistency, composure, intelligence, positional sense, and goalkeeping technique, which enables him to read the game, cover the goal well, and stop shots without having to resort to histrionics. Furthermore, he also known for his handling, and is effective at dealing with high balls, which enables him to come out and claim crosses and command his area well.
Ex-Roma goalkeeping coach Roberto Negrisolo has praised Alisson by calling him the 'Messi of goalkeepers', as he has the 'same mentality as Messi' and the ability to 'mark an era'. Furthermore, Negrisolo also compared him to former Italy goalkeeper Dino Zoff and Belgian goalkeeper Michel Preud'homme. His playing style has also drawn comparisons with compatriots Júlio César, Muriel Becker, and Claudio Taffarel in the media. The moniker "The Pelé of goalkeepers" has also been attached to him.