[5] The idea to build a stadium in the same district as the horse racing track belonged to the president of AC Milan at the time, Piero Pirelli.

From 1948 to 1955 engineers Armando Ronca and Ferruccio Calzolari developed the project for the second extension of the stadium, which was meant to increase the capacity from 50,000 to 150,000 visitors.

However, in recent years both Inter and Milan fans have called the stadium simply San Siro.

The Municipality of Milan entrusted the work to the architects Giancarlo Ragazzi and Enrico Hoffer, and to the engineer Leo Finzi.

To increase capacity, a third ring was built (only in the two curves and in the west grandstand) which rests on eleven support towers surrounded by helical ramps that allow access to the public.

Four of these eleven concrete towers were located at the corners to support a new roof, which has distinctive protruding red girders.

In 1996, a museum was opened inside the stadium charting Milan and Internazionale's history, with historical shirts, cups and trophies, shoes, art objects and souvenirs of all kinds on display to visitors.

[9] The reaction of Inter's fans to impending defeat in the 2005 match (throwing flares and other objects at Milan players and forcing the match to be abandoned)[10] earned the club a large fine and a four-game ban on spectators attending European fixtures there the following season.

The city was also the venue for the 1956 edition of the Latin Cup (also won by Milan), but those matches were played at Arena Civica.

[19] Milan and Internazionale announced their intention in June 2019 to build a new stadium to replace the San Siro.

The new 60,000 capacity stadium, which would be constructed next to the San Siro, was initially anticipated to cost US$800 million and be ready for the 2022–23 season,[20] although this did not come to pass.

San Siro is scheduled to host the opening ceremony of the 2026 Winter Olympics co-hosted by Milan.

[29] San Siro was the venue for the boxing match between Duilio Loi vs. Carlos Ortiz for the Junior Welterweight title in 1960.

[32] Afterwards it had the opportunity to host Bob Dylan and Santana in 1984, Bruce Springsteen in 1985, Genesis, Duran Duran and David Bowie in 1987, Michael Jackson in 1997, and in more recent times, the Red Hot Chili Peppers in 2004, U2 in 2005 and 2009, The Rolling Stones in 2006 and 2022, Madonna in 2009, Depeche Mode in 2009, 2013, 2017 and 2023, Muse in 2010, 2019, and 2023, Bon Jovi in 2013, Pearl Jam in 2014, Beyoncé in 2016, Coldplay in 2017 and 2023, Ed Sheeran in 2019, and Elton John in 2022 and Taylor Swift in 2024.