The former Barcelona man was relegated to second-choice right-back in North London following the arrival of Pedro Porro from Sporting Lisbon and was linked with an exit for a number of weeks.
The Saudi Pro League was mooted as a potential destination for Emerson, but AC Milan were always considered the frontrunners for the 25-year-old, who was involved in Spurs' pre-season tour of Asia despite the expectation of an exit.
A breakthrough in negotiations was eventually reached between the two clubs, and after being spotted heading to Milan for his medical, Royal has been confirmed as the Rossoneri's latest recruit.
The defender has penned a four-year contract at San Siro with a 12-month extension option until the summer of 2029, and he will sport the number 22 shirt during his time in red and black.
Emerson inherits Kaka shirt at Milan
That jersey was famously worn by Emerson's compatriot Kaka during his successful spell at Milan from 2002 to 2009, in which he won the Ballon d'Or, prior to which Edgar Davids also donned the 22.
Tottenham are believed to have pocketed a £13m fee through Emerson's sale, representing a slight loss on the €25m (£21.4m) they paid to prise him away from Barcelona three years ago.
Emerson arrived in North London after Spurs missed out on the signature of Takehiro Tomiyasu to Arsenal, and he departs with a record of four goals and two assists from 101 matches in all tournaments.
The 25-year-old scored once in 24 games in the 2023-24 campaign, during which his versatility came in handy, as he also played centrally and on the left as well as his favoured right flank.
However, Emerson only started 11 Premier League matches during Ange Postecoglou's debut season, and the arrivals of Radu Dragusin and Archie Gray bumped him further down the pecking order.
The Sao Paulo-born defender follows Strahinja Pavlovic and Alvaro Morata to Milan and could make his first-team debut for the Rossoneri on Saturday, when they open their Serie A campaign at home to Torino.
Could more Spurs players follow Emerson out?
Including loan transfers and players leaving upon the expiration of their contracts, Emerson's £13m move to Milan takes Tottenham's summer exits into the double figures, although he is just the second to leave for a fee after Joe Rodon joined Leeds United.
Postecoglou has also lost Tanguy Ndombele, Eric Dier, Japhet Tanganga, Ivan Perisic and Ryan Sessegnon on free transfers, while allowing Bryan Gil, Alejo Veliz and Pierre-Emile Hojbjerg to leave on loan, although the latter will join Marseille permanently next year.
The likes of Sergio Reguilon, Oliver Skipp and Giovani Lo Celso could also depart in the coming weeks, as well as Richarlison, who now faces additional competition up top from £65m new boy Dominic Solanke.
Tottenham open their 2024-25 Premier League season away to newly-promoted Leicester City on August 19.