Originally from Izumisano, Japan, Takumi Minamino joined Cerezo Osaka's youth set up at the age of twelve, and made his first team debut in 2012 at the age of seventeen.

Minamino made a total of 62 domestic appearances for the J League club but the 2014 season ended in disappointed as they were relegated. In January 2015 he moved to Europe joining Red Bull Salzburg, who said they had been tracking him for eighteen months. During the remainder of that 2014-15 season he scored three goals in fourteen appearances, establishing himself in a midfield role.

Over the next two seasons Minamino made 71 appearances, sometimes featuring as a striker and scoring 27 times. His club won successive league and cup doubles. During 2017-18 Minamino helped Salzburg to the title again and they also reached the semi finals of the Europa League. He signed a contract extension keeping him at the club until 2021, but including a release clause which Liverpool would later activate. 

Despite impressive domestic performances, Minamino did not establish himself in the Japan side until the end of 2018. He had made the preliminary squad of thirty for the 2014 World Cup, but not the final 22. His international appearances over the next three years amounted to just seven minutes of action, over two appearances as a substitute. In 2019 he helped Japan to the Asian Cup final, scoring his country's goal in the 3-1 defeat to Qatar.

During 2018/19 Salzburg won another league and cup double, with Minamino used in a much more attacking role. They then progressed to the group stages of the Champions League for the first time, being drawn in a group that included Liverpool. Minamino impressed in a 6-2 victory over Belgian side Genk, then scored at Anfield as his side came from 3-0 down to 3-3, only for the Reds to snatch a winner. 

On 18 December 2019 Minamino completed a medical at Liverpool and it was confirmed that he would join the club on 1 January 2020. He became Liverpool's first Japanese player and was handed the number 18 jersey, making his debut on 5 January against Everton in the FA Cup 3rd round at Anfield. He made ten Premier League appearances and finished the season with two championship medals, as Salzburg also finished as champions in Austria. Minamino scored his first goal for the Reds in the Community Shield against Arsenal on 29 August 2020, a game the Reds lost on penalties. After a half a season of failing to impress when given the chance at Anfield, Minamino was loaned to Southampton for the rest of the season for £500,000 in February 2021. Saints wanted an option to buy him in the summer but that was rejected by Liverpool.