On 27 August 2017, Nakajima moved abroad for the first time, signing a season-long loan with Portimonense of Portugal's Primeira Liga.[3] After scoring 10 goals and as many assists in 32 total matches for the team from the Algarve, he signed a permanent deal in May 2018.[4]
Al Duhail
In February 2019, Nakajima joined Qatar Stars League side Al Duhail[5] for a reported transfer fee of €35 million.[6] He played seven games for the eventual runners-up, and scored once in a 6–0 home win over Al Ahli on 28 February.[7]
Porto
On 5 July 2019, Porto announced an agreement with Al-Duhail for the acquisition of Nakajima's sports rights, in a €12 million transfer fee (50% of the player economic rights). He signed a five-year contract, keeping him contractually linked until 30 June 2024, with an €80 million release clause.[8][9]
Nakajima made his Porto debut on 13 August 2019 in the second leg of the UEFA Champions League third qualifying round away to Krasnodar, playing the full 90 minutes of a 3–2 loss that eliminated the team on the away goals rule.[10] He scored his first goal on 19 December 2019, the only one of a home win over Santa Clara in the fifth round of the Taça de Portugal, his 17th appearance.[11]
On 16 January 2021, Nakajima joined Al Ain of the UAE Pro League on a six-month loan deal including an optional €40 million transfer clause.[12] After his time in the Middle East was ended by a tibia break, on 25 August that year he returned on loan to Portimonense for a season.[13]
Antalyaspor
Nakajima signed for Turkish club Antalyaspor in 2022. He made his debut on 18 September 2022 against Adana Demirspor, coming on the 59th minute only to be sent off in just 20 seconds after receiving a red card for a late sliding tackle.[14]
Urawa Red Diamonds
On 25 July 2023, J1 League side Urawa Red Diamonds announced the signing of Nakajima. The duration of the contract was undisclosed.[15]
In March 2015, he played two matches in the AFC U-23 Championship qualification and scored a double against Vietnam.[29][30] The team reached the first place of the group and was granted the qualification for the 2016 AFC U-23 Championship. In January 2016, he participated in the championship, scoring a double in the extra-time of the quarter-finals match against Iraq[31] and eventually won the competition
with a 3–2 triumph against South Korea.[32] Nakajima was also crown the Most Valuable Player of the Tournament.[33]
In August 2016, he was selected for the Japanese Olympic national team (under-23) that competed in the 2016 Summer Olympics in Rio de Janeiro. He played three matches and scored a goal against Colombia, while the team came third in the group stage.[34][35][36]
Senior career
On 15 March 2018, Nakajima was called by national manager Vahid Halilhodžić for upcoming matches against Mali and Ukraine.[37] Eight days later, he debuted and scored his first goal for Japan national team against Mali in a 1–1 draw.[38]
Hajime Moriyasu named Nakajima in the squad for the 2019 Copa América in Brazil, which Japan guest entered with a mainly under-23 team. He scored the opening goal against Ecuador in the last group game in Belo Horizonte, but the 1–1 draw eliminated the team.[39]