The 19-year-old has signed a seven-year contract, keeping him at the Bernabéu until 30 June 2033. It caps a chaotic few weeks in which two Premier League and Champions League heavyweights also chased his signature: Liverpool saw an early £69m offer knocked back in June as they hunted a long-term replacement for Mohamed Salah, who has since left for Trabzonspor in Turkey, while Paris St-Germain walked away from the race entirely on Sunday once Leipzig rebuffed their £102.5m proposal.
Should Real end up paying the full £120m, Diomande would become the fourth most expensive player in football history, behind Paris St-Germain pair Neymar and Kylian Mbappe and Liverpool's Alexander Isak. He would also surpass the £72m Arsenal paid Lille for Nicolas Pepe in 2019 to become the most expensive African player ever sold, and eclipse the £115m Real handed Borussia Dortmund for Jude Bellingham in 2023 to set a new club-record fee.
The winger's rise has been remarkably rapid. Just two years ago he was playing academy football in Daytona Beach, Florida, before a move to Spanish side Leganés opened the door to a switch to Leipzig.
He repaid that investment with 12 goals and eight assists in the Bundesliga last season, form that carried into a standout World Cup with Ivory Coast and turned him into one of the most sought-after teenagers in the game.
Diomande becomes the latest arrival in a busy summer overhaul at the Bernabéu, following the signings of Bernardo Silva, Ibrahima Konaté, Denzel Dumfries and Marc Cucurella, as head coach José Mourinho looks to end Real's two-year wait for a major trophy. The fee also makes Diomande the second most expensive player to leave the Bundesliga, behind only Ousmane Dembélé's €148m move from Borussia Dortmund to Barcelona in 2017.
The transfer has not been without complication. An unresolved dispute over representation rights has rumbled on behind the scenes, with the Maxidel Management agency, which brokered Diomande's switch from Leganés to Leipzig last year, and his current advisers at Roc Nation both said to be laying claim to a share of the proceeds.
Real were also linked with a move for Bayern Munich winger Michael Olise earlier in the window, but the German club consistently refused to make him available for sale, redirecting Florentino Pérez's attention towards Diomande instead.