Wearing black and blue stripes, they have played in the Italian first division since 1908. The club have won 29 national trophies including eighteen Italian league titles, six Italian Cups and five Italian Super Cups. At the international level, they have won three European Cup/Champions League; first of all two back-to-back European Cups in 1964 and 1965 and then, after 45 years, in 2010, completing an unprecedented (for an Italian team) treble after winning in the same season the Coppa Italia and the Scudetto. The club won also three UEFA Cups in 1991, 1994 and 1998, and two Intercontinental Cups in 1964 and 1965.

Inter play in the largest stadium in Italy, the Giuseppe Meazza stadium (also known as San Siro) and train at the Angelo Moratti Sports Center (also known as La Pinetina), a training facility 30 kilometers away in Appiano Gentile, near Como.

The club was founded on 9 March 1908 as Football Club Internazionale Milano, following a "schism" from the Milan Cricket and Football Club (43 members). A group of Italians and Swiss (Giorgio Muggiani, a painter who also designed the club's logo, Bossard, Lana, Bertoloni, De Olma, Enrico Hintermann, Arturo Hintermann, Carlo Hintermann, Pietro Dell'Oro, Hugo and Hans Rietmann, Voelkel, Maner, Wipf, and Carlo Ardussi) were unhappy about the domination of Italians in the AC Milan team, and broke away from them, leading to the creation of Internazionale. From the beginning, the club was open to foreign players and thus lived up to its founding name.

The club won its very first Scudetto (championship) in 1910 and its second in 1920. The captain and coach of the first Scudetto was Virgilio Fossati, who fell in World War I. In 1922 Inter were in Group B of the Serie A and came in last place after picking up only 11 points in the season. The last place team of each group was to be automatically relegated. The second last place teams were placed in a pre-relegation 'salvation' tournament. Inter and La Gazzetta dello Sport editor (Colombo) petitioned the FIGC to allow Inter to participate in Serie A the following year as a year in Serie B would have been financially detrimental. The FIGC saved Inter some weeks prior to the season starting by allowing them to remain in Serie A in 1923. In 1928, during the Fascist era, the club was forced to merge with the Milanese Unione Sportiva and was renamed Ambrosiana SS Milano. They wore white shirts around this time with a red cross emblazoned on it. This shirt design was inspired by the flag and coat of arms of the city of Milan, which in turn is derived from the flag of the patron saint of Milan, St. Ambrose and dates back to the 4th century AD. The new upcoming President Oreste Simonotti decided to change name to AS Ambrosiana in 1929. However, supporters continued to call the team "Inter", and in 1931, new president Pozzani caved to shareholder pressure and changed the name to AS Ambrosiana-Inter.

Their first Coppa Italia (Italian Cup) was won in 1938–39, led by Giuseppe Meazza, after whom the San Siro stadium is officially named, and a fifth league championship followed in 1940, despite an injury to Meazza. After the end of World War II the club re-emerged under a name close to their original one, Internazionale FC Milano, which they have kept ever since.

Following the war, Internazionale won their sixth championship in 1953 and the seventh in 1954. Following these titles, Inter were to embark upon the best years of their history, affectionately known as the era of La Grande Inter (The Great Inter). During this period with Helenio Herrera as head coach, the club won three league championships in 1963, 1965 and 1966. The most famous moments during this decade also include Inter's two back-to-back European Cup wins. In 1964, Inter won the first of those tournaments, playing against the famous Spanish club Real Madrid. The next season, playing in their home stadium, the San Siro, they defeated two-time former champions Benfica.In 1966–67 season Internazionale got to the European Cup final again but lost 2–1 to Celtic in Lisbon.

Following the golden era of the 1960s, Inter managed to win their 11th league title in 1971 and their twelfth in 1980. Inter were defeated for the second time in five years in the final of the European Cup, going down 2–0 to Johan Cruyff's Ajax in 1972. During the 1970s and the 1980s, Inter also added two Coppa Italias to their tally in 1977–78 and 1981–82.

Led by the German duo of Andreas Brehme and Lothar Matthäus, and Argentine Ramón Díaz, Inter captured the 1989 Serie A championship under coach Giovanni Trapattoni. Fellow German Jürgen Klinsmann and the Italian Supercup were added the following season but to little avail as Inter did not manage to defend their title.

The 1990s were a period of disappointment for the club. While their great rivals Milan and Juventus were achieving success both domestically and in Europe, Inter were left behind, with some mediocre positions in the standings, their worst finishes being in 1993–94 when they were just one point from relegation. Nevertheless, they achieved some European success in that decade with three UEFA Cup victories in 1991, 1994, and 1998.

With Massimo Moratti's takeover from Ernesto Pellegrini in 1995, Inter were promised more success with many high profile signings such as Ronaldo, Christian Vieri, and Hernán Crespo, with Inter twice breaking the world record transfer fee in this period.[citation needed] €19.5 million for Ronaldo from Barcelona in 1997 and €31 million for Christian Vieri from Lazio in 1999. However, the 1990s remained a decade of disappointment and is the only decade in Inter's history in which they failed to win a single Serie A championship. For Inter fans, it was difficult to identify who in particular might be to blame for these troubled times and this led to some icy relations between president, managers, and even some individual players.