[7] At age 16 years and 32 days,[8] Maupay made his professional debut as an injury-time substitute for Éric Bauthéac during the 3–2 win.

[15] He had a good start to the 2016–17 season, scoring 10 goals in his opening 21 matches,[17] winning the August 2016 UNFP Ligue 2 Player of the Month award and receiving nominations in September,[18] October and December.

[6][17][22] On 14 July 2017, Maupay moved to England to join Championship club Brentford on a four-year contract for an undisclosed fee,[16] reported to be £1.6 million.

[23] The club's France scout Brendan MacFarlane, who would also go on to identify Saïd Benrahma, Julian Jeanvier and Bryan Mbeumo, played a key role in the identification of the player as a target.

[31][35][36] On 5 August 2019, Maupay moved to Premier League club Brighton & Hove Albion on undisclosed terms,[37] for a fee reported to be in the region of £20 million on a four-year deal.

[40] Maupay scored his 10th goal of the season in a 1–1 away draw against Southampton on 16 July 2020, helping Brighton earn an important point towards safety.

[42] On 26 September, Manchester United were given a penalty after the final whistle due to VAR deeming Maupay to have committed handball right at the end.

[47] Maupay's opener in the 2–0 away victory over Watford on 12 February 2022 was his 26th Premier League goal for the Albion, equalling Glenn Murray's club record.

"[50][51][52] After being left on the bench for both North London fixtures he returned to the starting line-up on 24 April, playing 85 minutes of the 2–2 home draw against Southampton.

[53] Maupay signed for Premier League club Everton on 26 August 2022 on a three-year contract with an option of a further year for an undisclosed fee.

[61] In February 2022, Maupay reportedly put in a personal request to Argentina boss Lionel Scaloni to consider selecting him for the national team.

A joint investigation by the Premier League and authorities in Singapore identified the culprit as 19-year-old Derek Ng, who was given a nine-month probation order.