[7] On 11 July 2018, during the summer transfer window, it was announced that Guendouzi had joined Premier League club Arsenal for an undisclosed fee, believed to be in the region of £7 million, plus bonuses.

[12] On 20 June 2020, following a post-match altercation with Brighton player Neal Maupay, Guendouzi was excluded from Arsenal training and left out of the club's match-day squads due to a history of issues with his "attitude and general conduct.

[23] On 21 April 2024, as per reports from multiple sources, such as Calciomercato.com & TMW, the management at Lazio decided to secure Guendouzi's services from the French club Marseille, after activating his conditional buyout clause.

To activate the stated clause, Lazio were to at least required to finish twelfth in the current Serie A table, which the club did so, after successfully triumphing 1-0 over Genoa two days earlier, on 19 April.

[26] On 2 September 2019, Guendouzi was called up to the French senior side for the first time to replace the injured Paul Pogba for UEFA Euro 2020 qualifiers against Albania and Andorra.

Guendouzi was recalled to the France side on 1 September 2021, to replace the injured Corentin Tolisso for World Cup Qualification matches against Bosnia, Ukraine and Finland.

[30] Guendouzi has a hatred for losing, an attitude and mentality which he accredits his success as professional player; although he has been accused of letting his competitive nature get the better of him.

[31] Emmanuel Petit described Guendouzi's personality as "volcanic";[31] his high-profile disciplinary incidents whilst playing in England gave him the reputation of a player that lacks self-control.