In 2018, Morita joinedKawasaki Frontale. On 10 February, he made his professional debut as a substitute in theJapanese Super Cup againstCerezo Osaka. On 14 April, he made his first start in the league match againstVegalta Sendai.[3] After that, he managed to secure an active role in the team, and they would go on to win theJ1 League title in 2018. In 2020, he was selected in theJ-League Best Eleven,[4] along with eight other Kawasaki players as they would win the J1 League title again.
On 8 January 2021, it was announced that Morita would sign for Portuguese clubCD Santa Clara, in thePrimeira Liga.[5] When he made his debut on 25 January, he netted his first goal for the club, scoring the winner in the 89th minute of a 2–1 victory overRio Ave.[6]
On 1 July 2022, it was announced that he would joinSporting CP on a permanent transfer.[7] He would go on to make his debut for the club against SC Braga on 7 August.[8] On 7 September, he made hisChampions League debut againstEintracht Frankfurt.[9] On 30 September, he scored his first goal for the club in a win againstGil Vicente.[10]
On 2 September 2018,Ryota Oshima andHotaru Yamaguchi withdrew from the national team due to injury; Morita was called up to theJapan national team in their place for the first time in his first year as a professional.[11] He made his national team debut on 11 September, coming on againstCosta Rica, the first game under new coachHajime Moriyasu.
In January 2019, he was called up to the Japan national team for theAFC Asian Cup 2019 but withdrew due to injury.[12]
In March 2021, he was called up to the national team for the first time in just under two years, and on 30 March, he scored his first goal for the national team in a 14–0 win againstMongolia in the2022 FIFA World Cup Asian Qualifiers.[13]