[9][11] In his third year at Higashiyama High School, Kamada was appointed captain, but they finished at the bottom of the league table with 2 wins and 13 losses.

[9][13][14] At the end of the 2014 season, Kamada's performance at Higashiyama High School having impressed many, he supposedly attracted interest from at least five J.

[19] He made his Sagan Tosu debut, coming on as a 75th-minute substitute, in a 1–0 loss against Albirex Niigata in the J.League Cup on 8 April.

[44] He made his last appearance of the season against Urawa Red Diamonds on 25 June, setting up the club's first goal of the game in a 2–1 win.

[46] In June 2017, Kamada joined Bundesliga club Eintracht Frankfurt, signing a four-year contract running until 2021.

[46] Kamada made his Eintracht Frankfurt debut in the first round of the DFB–Pokal, starting a match and played 73 minutes before being substituted, in a 3–0 win against TuS Erndtebrück.

In order to receive first team football, Kamada was loaned out to Belgian side Sint-Truiden for the rest of the 2018–19 season on 1 September 2018.

[55] Since making his debut for Sint-Truiden, Kamada quickly established himself in the first team, playing in either midfielder and striker positions.

[61] In the Group A league play-offs, Kamada later scored three goals, including a brace, in a 2–2 draw against Westerlo on 6 April 2019.

Since the start of the 2019–20 season, Kamada returned from a loan spell at Sint-Truiden and quickly became a first team regular for Eintracht Frankfurt, playing as a second striker.

[70] Against Red Bull Salzburg in the second leg of UEFA Europa League's Round of 32 match, Kamada scored a hat–trick, in a 4–1 win.

[79] Three days before the start of the 2020–21 season, Kamada signed a contract extension with Eintracht Frankfurt, keeping him until 2023, with manager Hütter played a factor to his decision.

[80] A week later against Hertha BSC on 25 September 2020, he played a key role to match by setting up two goals in a 3–1 win.

[83] Kamada played a role in a match against Union Berlin when he sets up two goals, as the club drew 3–3 on 28 November 2020.

[86] In the second half of the season, Kamada continued alternating between a starting and a substitute role despite competing with Amin Younes.

[88] After missing one match due to lumbago, Kamada scored on his return from injury, in a 1–1 draw against RB Leipzig on 14 March.

[89] Despite scoring on his return, he played in the right–midfield position, which Manager Hütter acknowledged the negativity criticism from Frankfurter Rundschau, describing it as "a failed experiment".

[97] After missing one match due to a torn muscle fibre, Kamada returned to the starting line–up from injury, in a 2–0 loss against VfL Wolfsburg on 12 February 2022.

[100] On 14 April 2022, he set up one of the goals for Filip Kostić as the club defeated Barcelona 3–2 at the Camp Nou and 4–3 on aggregate in the UEFA Europa League to qualify for the semi-finals.

[102] Eventually, Eintracht Frankfurt won the tournament after beating Rangers 5–4 on penalty shootouts in the final, in which he scored one of them.

[106] Between 15 October 2022 and 1 November 2022, he scored a total of six goals in all competitions, including the UEFA Champions League group stage when he scored in the last three consecutive matches against Tottenham Hotspur, Marseille and Sporting CP, which helped his club to reach the knockout phase.

[107] After missing one match due to an illness in early–November, Kamada returned to the starting line–up against Hoffenheim on 9 November 2022 and set up one of the goals, in a 4–2 win.

[117] He was linked with a move to European clubs, such as, Benfica, Borussia Dortmund, FC Barcelona and Atlético Madrid.

[123] Kamada made his debut for Lazio, starting a match and played 54 minutes before being substituted, in a 2–1 loss against US Lecce.

[126] With his playing time coming from the substitute bench, Kamada was linked with a move to Galatasaray in the January transfer window, but the move fell through, due to the club's CEO Claudio Lotito demanded 10 million euros, as well as, the player, himself, wanted to stay at Lazio.

By the end of the 2023–24 season, Lazio CEO Claudio Lotito claimed that Kamada had demanded a bonus of €2.5 million to extend his contract for another year, while declaring that he would "send away all the players who turn out to be mercenaries".

[133][134][135] He made his debut for Crystal Palace, starting a match and played 65 minutes before being substituted, in a 2–1 loss against Brentford in the opening game of the season.

[158] He was in the starting eleven squad when the Samurai Blues win 2–1 over Spain to help his country reached the knockout phase.

[160] Reflecting on playing in the World Cup, he expressed his disappointment of being the only starter in the attacking position to not score or provide assists.

[167] Kamada's father, Fukushige, was once a footballer and worked for the seniors and juniors at Osaka University of Physical Education.