Early career in 2015 Born in
Esmeraldas, Estupiñán joined
LDU Quito's youth setup in 2011, aged 13. He was promoted to the first team ahead of the
2015 season, and made his professional debut on 1 February of that year by starting in a 1–0 home win against
El Nacional.
Watford and following loans An undisputed starter for the club, Estupiñán was sold to
Premier League club
Watford on 29 July 2016, being immediately loaned to
Granada CF and assigned to the latter's
B-team in
Segunda División B. Estupiñán made his
La Liga debut on 5 April 2017, starting in a 0–0 away draw against
Deportivo de La Coruña. On 17 July, he was loaned to
Segunda División side
UD Almería for one year. On 9 August 2018, Estupiñán agreed to a one-year loan deal with
RCD Mallorca in the second division. The following 3 July, after
achieving promotion, he signed a two-year loan deal with
CA Osasuna, also freshly promoted.
Villarreal On 16 September 2020, Estupiñán signed a seven-year contract with Spanish side
Villarreal for an initial fee of £14.9 million. During his spell at the Valencian club, Estupiñán was a member of the squad that won the
2020–21 UEFA Europa League and reached the semi-finals of the
2021–22 UEFA Champions League.
Brighton and Hove Albion On 16 August 2022, Estupiñán signed a five-year contract with
Premier League side
Brighton & Hove Albion for an undisclosed fee. He made his debut four days later, coming on and replacing
Adam Lallana in the 63rd minute in the 2–0 away win over
West Ham United. Estupiñán made his first start for the "Seagulls" on 27 August, helping Brighton to another win and clean sheet in the 1–0 home victory over
Leeds United. Estupiñán assisted
returning World Cup champion Alexis Mac Allister's flick-in in the 5–1 away victory over
EFL Championship side
Middlesbrough in the
FA Cup third round on 7 January 2023. Two weeks later, on his 25th birthday, he made a brace of assists, setting up both
Kaoru Mitoma's opening goal and
Evan Ferguson's late equaliser in the 2–2 away draw at
Leicester City in the league. On 29 January, Estupiñán recorded his fourth assist of the season in a 2–1 victory over
Liverpool, helping Brighton to advance to the fifth round of the
FA Cup. Two games later on 11 February, he added a further assist to his tally a 1–1 away draw against Crystal Palace. Early on in the game he had a goal wrongly ruled out by
John Brooks of
VAR after the official drew the offside lines against the wrong player. Brooks was later dropped for his next two matches. Estupiñán scored his first goal for the Albion on 14 May, hitting in stoppage time, scoring the third in the 3–0 away win at
Arsenal, while assisting
Julio Enciso's opener. After setting up Mitoma's opener, Estupiñán scored his second Brighton goal in their second match of the
2023–24 season on 19 August, in the 4–1 victory away at
Wolverhampton Wanderers. On 28 December, after months out due to injury, Estupiñán scored a long-range goal after coming on as a substitute at halftime in a 4–2 win against
Tottenham Hotspur.
AC Milan On 24 July 2025, Estupiñán signed a five-year contract with Italian
Serie A side
AC Milan for an undisclosed fee, reported to be at least £17 million. This signing made him the first Ecuadorian in the club's history. On 8 March 2026, he scored his first goal with the club during a 1–0 home win Serie A match against
Inter Milan, on the
Derby della Madonnina. ==International career==