[11] The team was founded in early 1925 by Magallanes' footballer David Arellano, who led a group of young players leaving that club after institutional problems.

[14] Initially the team played friendly games, but in 1926 Colo-Colo they took part in their first competition, the Metropolitan League of Honour, where they were proclaimed champions (unbeaten) and earned the nickname of "invincible".

However, on 2 May, during an exhibition match against Real Unión Deportiva at Valladolid, the team founder and captain David Arellano was critically injured after suffering a collision with an opposing player, which caused him peritonitis.

In the 1931–32 season, Colo-Colo suffered its first institutional crisis due to financial problems, which led to a salary reduction for first team footballers and board members, with their consequent resistance.

[28] Two seasons later, in 1939, Colo-Colo won the league title for a second time, now under the guidance of the Hungarian coach Francisco Platko,[29] and with Alfonso Domínguez as goalscorer with 20 goals in 24 matches.

[33] The following year Colo-Colo organized the South American Club Championship – Copa Libertadores background – in Santiago,[34] which brought together the 1947 continent's champions.

[35] In the early 1950s, club's president Antonio Labán hired Newcastle United striker George Robledo, paying £25,000 for its signing.

[44] In 1972, under the orders of coach Luis Álamos[45] and boasting star players in play maker Francisco Valdés and goal scorer Carlos Caszely,[46] the club won another championship.

[49] After Colo-Colo's brilliant Copa campaign, the club fell into an institutional crisis unable to replicate its success on the pitch failing to win another league title until 1979.

[50] That team featured the talented Brazilian midfielder Severino Vasconcelos alongside Carlos Caszely returning from his stint in Spanish football.

On 30 September 1989, the Estadio Monumental was re-inaugurated with an exhibition match against Peñarol, which Colo-Colo won 2–1[3] with goals by Marcelo Barticciotto and Leonel Herrera, the son of a legendary 1970s former defender of the same name.

Eduardo Menichetti was president of the club between 1990–1995[56] and Croatian Mirko Jozić arrived as coach, leading the team towards its first Bicampeonato for winning two national championship league titles in a row.

[57] On 5 June 1991, after beating Olimpia 3–0 at the Monumental with two goals scored by Luis Pérez and one by Leonel Herrera, Colo-Colo became the first Chilean team to win a Copa Libertadores.

[59] The following season, the club won the Recopa Sudamericana, after beating Brazil's Cruzeiro in a penalty shootout, and also obtained the Copa Interamericana, after winning 3–1 against Puebla in Mexico.

[60] After Jozić's departure came a brief drought in national league titles, but the team managed to achieve an unforgettable 3–0 win over arch rivals Universidad de Chile in the 1995 season.

A court judge named Juan Carlos Saffie as bankruptcy trustee and administrator responsible for the institution not lose its legal status.

[64] With the Argentine Claudio Borghi appointed coach in 2006, and with players like Matías Fernández and Humberto Suazo, Colo-Colo played scintillating football and obtained the Bicampeonato winning the Apertura[67] and Clausura tournaments.

The team however reached the tournament play-off finals against Universidad Católica, beating them 4–2 at the Santa Laura, with players like Esteban Paredes, Macnelly Torres and Ezequiel Miralles, coached by Hugo Tocalli.

In 1956, club's president Antonio Labán acquired a 28 ha terrain at Macul, close to the intersection between Vicuña Mackenna and Departamental.

It was inaugurated in a league match 1975 which Colo-Colo win 1–0 over Deportes Aviación with Juan Carlos Orellana, who become the first player to score a goal in Monumental's history.

The stadium was called Monumental David Arellano in honour of its founder and its definitive inauguration was in a match against Uruguay's Peñarol which Colo-Colo won 2–1.

Current squad of Colo-Colo as of 22 January 2025 (edit) Sources: Official Web Site Manager: Jorge Almirón Note: Flags indicate national team as defined under FIFA eligibility rules; some limited exceptions apply.

Colo-Colo is the club with the largest following in Chile, with approximately 42% of the total Chilean football fans according to research published in August 2012 by Spanish newspaper agency Marca.

They attended Colo-Colo's games and generally rioted, especially in derbies, turning Estadio Monumental surroundings into battlefields against the military police.

Although the first confrontation between the two clubs dates back to 1935, the rivalry began to develop in the 1940s and 1950s, with the match played on 11 November 1959, being the climax of a series of disagreements between the two institutions.

That match, valid for the definition of that year's title, ended with a 2-1 victory for Universidad de Chile, which was the first of a series of good results for the "Azules" over Colo-Colo.