It is one of the most successful and iconic clubs in Colombia, making it one of the largest sports entities in the country and one of the most important in South America.

The team's origins date back to the 1920s, but it began to be called Los Millonarios in 1937 when its name was Club Deportivo Municipal.

[2] Millonarios won their first local title in 1949 and shortly afterwards formed a team known as the "Ballet Azul", which was a reference of great importance worldwide during the first part of the 1950s, being considered by various South American and European specialists as the best team in the world when it achieved a large number of triumphs and international achievements of great importance for the time.

[3][4] Alfredo Di Stefano, who is widely regarded as one of the greatest footballers of all time, joined Millonarios in 1949 and played for the team until 1953.

It has been included in lists of the best football clubs of all time made by major international sports media, being the only Colombian team present on them.

The team made their debut in February of that year at the Central American and Caribbean Games in Panama City, where they won the bronze medal in a stellar performance.

Upon returning from Panama and with the team on the brink of disbandment, Izquierdo saw an opportunity in the upcoming first edition of the Bolivarian Games to be held in Bogotá.

This was a significant moment for football in the city, as it marked the first time that a team from Bogotá (and from the country) had played with foreign players.

In 1939, the nickname "Los Millonarios" (The Millionaires) was born when Vicente Lucífero met with the team's board of directors every Thursday to negotiate payments.

He wanted to ensure that the Colombian players' salaries matched those of the foreigners, which caused Luis Camacho Montoya, the sports editor of El Tiempo newspaper, to strongly criticize the team for its disassociation from the municipality.

In 1932, seven years prior, the Argentine club River Plate had already adopted the same nickname for making big signings at that time.

On 13 August 1939, in a meeting at the "El Gato Negro" café (16th Street with Eighth Avenue), the team officially adopted the name "Los Millonarios" as part of a relaunch and re-founding of the club, which took place on that date when they defeated Deportivo Barranquilla 6–0 with goals from Luis Timón (1–0 and 5–0), Martínez, Ruiz Díaz, Zapata, and an own goal by López.

Since its creation, Millonarios has become one of Colombia's most important teams by winning titles in amateur league tournaments, international matches, and various tours throughout the country, achieving significant triumphs.

During this period the squad was known as The Blue Ballet, which featured great players such as Alfredo Di Stefano, Adolfo Pedernera, Néstor Rossi, Julio Cozzi, Antonio "Maestrico" Báez, Hugo Reyes, Reinaldo Mourin and other figures in Argentina, mainly from River Plate.

Thanks to the great football these players showed on the field, Millonarios was named by several media outlets in South America and Europe, as the best team in the world in the early 1950s.

In 1952, a group of Venezuelan sports entrepreneurs created the Small Club World Cup, a friendly competition that brought together leading European and South American teams.

They came very close to winning the league title in 1994, but Atlético Nacional snatched it from them on bonus points as both teams won their matches on the final day.

Although they had a scare in the first stage, where they just barely edged Peruvian club Coronel Bolognesi on penalties, they went on to eliminate several powerful teams, including beating rivals Nacional 3–2 and then shutting out Brazilian champions São Paulo 3–0 in the quarter-finals.

Plagued by financial problems, and with no major titles in the last decade, as well as having failed to qualify for the playoffs in the last seven seasons, the club finally initiated a bankruptcy process that led to it being bought by a society composed of about 4,000 fans, Azul & Blanco S.A.

This came as a relief after an embarrassing 8–0 defeat to Real Madrid in a friendly match in September to honor Alfredo Di Stéfano.

After a very difficult series of matches, the team finished the playoffs with ten points, equal with Deportivo Pasto, but reached the finals on better goal difference, which were to be played against Independiente Medellín.

[13] In the 2017 Finalización, Millonarios achieved their fifteenth league title after defeating Santa Fe in a final that saw two goals at the end of the second half.

That league championship was immediately followed with their first Superliga Colombiana title, defeating Atlético Nacional over two legs to win the 2018 edition of the competition.

After a 2019 league campaign that saw Millonarios top the first stage of the Apertura tournament but ultimately miss out on the final series and later fail to qualify for the Finalización semi-finals, manager Jorge Luis Pinto resigned and was replaced by former player Alberto Gamero for the 2020 season.

[14] Millonarios's first season under Gamero did not bring the expected results, as the team failed to advance to the knockout stage of the league and had to win a tournament involving the eliminated sides in order to get a chance to qualify for the 2021 Copa Sudamericana.

Although they managed to win the consolation tournament, they missed out on Copa Sudamericana qualification after losing the playoff to Deportivo Cali.

[17] Millonarios's sixteenth league title came in the 2023 Apertura tournament, placing second in the first stage with 38 points in 20 matches and winning their semi-final group where they played América de Cali, Boyacá Chicó, and Independiente Medellín.

With Atlético Nacional as their rival for the finals, and after draws in both legs of the series (0–0 in Medellín and 1–1 in Bogotá), Millonarios won the ensuing penalty shootout by a 3–2 score to claim the league championship.

In the second leg, played on 17 December, Millonarios came back from an adverse result twice, first with a goal by Andrés Cadavid, and finally with one by Henry Rojas, for a 3–2 aggregate score, with which they won their 15th league championship.