[4] Having arrived at Atlético Madrid's youth system at the age of eight, he made his debut for the first team on 19 September 2009, playing in the second half of a 5–2 away loss against FC Barcelona after coming on as a substitute for Paulo Assunção.

[6][7][8] Koke scored his first league goal for Atlético against Sevilla FC on 26 February 2011, his 47th-minute header from a Diego Forlán cross made it 1–1 in an eventual 2–2 home draw.

[13] Aged only 20/21, Koke started in 38 of his 48 official appearances during 2012–13 and scored three goals – this included 112 minutes of play in the final of the Copa del Rey, won against Real Madrid at the Santiago Bernabéu.

[17] His performances in October earned him the accolade of La Liga Player of the Month, while Simeone won the equivalent managerial award;[18] on 3 March 2014, he scored to help his team to a 2–2 home draw in the Derbi madrileño against Real Madrid.

[36] Koke played his 400th official match for the club on 20 January 2019 – becoming the youngest player to do so in the process, at the age of 27 – scoring once and providing one assist in a 3–0 away defeat of SD Huesca.

[40] The following 12 May, as his side neared the league title, he made his 500th appearance in a 2–1 home victory over Real Sociedad, a feat only done before by Adelardo Rodríguez;[41] he broke the former's record on 1 October 2022 in his 554th match, a 2–0 win at Sevilla.

[46] Koke featured in the Spanish team at the 2012 Summer Olympics in London,[47] playing all three games as the tournament ended at the group stage for the nation.

[50] His first competitive appearance for La Furia Roja came on 6 September of that year, as he played the full 90 minutes in a 2014 FIFA World Cup qualifier in Finland that ended with a 2–0 win.

[53] On 19 June, he made his debut in the tournament after replacing Xabi Alonso at half-time as the champions trailed 0–2 to Chile at the Maracanã in the second group game, but could not change the scoreline as elimination was confirmed.

[23][62] Koke earned the plaudits of his peers, including Barcelona's Xavi who regarded him as his successor: He has everything: talent, physical ability, he is a footballer of the present and the future...