O'Higgins

Establishment

On 7 April 1955, after the merger of Rancagua's cross–town rival: O'Higgins Braden (that was born in 1954 from the merger between Braden and Instituto O'Higgins) and América de Rancagua, the club was founded thanks to Carlos Dittborn, the president of the Asociación Central de Football, who offered to put the name of the O'Higgins, which represents workers of Codelco in the city, under the name of Braden Copper; the name was also chosen in reference to the country's founding father and supreme director Bernardo O'Higgins, an important character of the Colonial Chile during the 1810s, who also identified with the city of Rancagua.

The colors of the club were originally from the Instituto O'Higgins, which were red, blue, and white. However, the Football Federation of Chile prohibited using the colors of the national team, so the club directors decided that the uniform would be sky blue, based on Uruguay's uniform, earning then the nickname of La Celeste. The stadium was named Estadio Braden Copper Company after the name of the company from its opening until the 1962 FIFA World Cup, when the name was changed to its current name, Estadio El Teniente, based on the El Teniente mine.

On 21 April 1955, the Asociación Central de Football decided that the team would play in the Primera División for the next season, with the first president being Nicolás Abumohor and the first head coach being Francisco Hormazábal. Their first game in the Campeonato Nacional was a 2–0 loss to Unión Española on 8 May 1955. Their first win came on 22 May of that same year, a 3–2 home victory against Ferrobádminton. In their first league tournament, the club finished ninth in the table, which put them in the relegation play-offs, where they earned their permanence in the top tier.

First seasons, relegations, and comebacks

The first great season of the club was in the 1959 season, where the club finished in fourth place under the orders of Argentine coach José Salerno, only four points behind league champion Universidad de Chile and behind third-placed team Santiago Wanderers on goal difference, making this one of its most successful Primera División campaigns, with José Benito Ríos as the key player and top scorer of the tournament with 22 goals.

A few seasons later, the team was relegated to the Segunda División after a poor campaign in 1963. The next season, with the signings of the defender Federico Vairo and the attacking midfielder Mario Desiderio, both from the Argentine Primera División, the team returned to Primera División. In special, the performances of Vairo consecrated him as the best footballer in the club's history according to the supporters of Rancagua, who chose the Rosarian centre back with the honour in 1999. Since the promotion in 1964, the club had average seasons, finishing mid-table, despite suffering the departures of Federico Vairo and Mario Desiderio to the Colombian side Deportivo Cali in 1966.

In the 1973 season, under the orders of the coaches Luis Vera and Jorge Aretio, O'Higgins and Huachipato both finished in third place behind of Unión Española and Colo-Colo, its best result since the 1959 season. In the 1975 season, the club was relegated again, but returned for the 1977 season after finishing runner up of the 1976 Primera B. After a notable 1978 tournament, where the team finished third in the league with Luis Santibáñez as head coach, it achieved qualification to the following edition of the Copa Libertadores by winning the Liguilla Pre-Libertadores, in which they achieved their biggest win for an international contest against Deportivo Galicia, beating the Venezuelan side 6–0 at El Teniente, and also achieved its most important away win for an international tournament, winning 1–0 in Valencia to the same Galicia. In the following season the club reached the fifth place in the league with Santibáñez as head coach again, qualifying to the 1980 Copa Libertadores via the Libertadores Liguilla after a notable unbeaten run of five matches, and winning the Liguilla over another strongers clubs, Universidad de Chile, Cobreloa and Unión Española.

Copa Libertadores appearances, Copa Chile finals

While managing indifferent league form in the early 1980s, the club had its first South American success in the form of the Copa Libertadores. In the 1980 edition, O'Higgins reached the semi-finals, after overcoming the group stage where they faced Colo-Colo, Cerro Porteño and Sol de América, only by goal difference, since all the teams had obtained 6 points (2 wins, 2 draws, 2 losses), they managed to advance to the semi-finals of the competition for the first time. Key players such as Miguel Ángel Neira (the team's top scorer with 3 goals in the tournament), Juvenal Vargas, Juan Rogelio Núñez, the Uruguayans Nelson Acosta and Washington Olivera, the Argentine goalkeeper Miguel Leyes and the defender with participations in the Chilean national team René Serrano were the backbone of the great participation of the sky-blue team. In the second phase they faced Club Nacional de Football and Club Olimpia, losing in all four games without being able to score goals in the definition phase. This is the best historical participation of the club in the most prestigious continental tournament.

During the 1984 edition of the Libertadores, the club finished last in its group, which was made up of fellow Chileans Universidad Católica, and Bolivian clubs Bolivar and Blooming. In the league, the team had poor campaigns from 1981 to 1983, although the club defeated Colo-Colo 6–1 in the 1983 season, and reached their first Copa Chile final, where it lost to Universidad Catolica in a liguilla group.

After financial problems with Codelco, the company owner of the club, the club was relegated to the Primera B in the 1985 season, with the possibility of being relegated to the Tercera División for another controversy related to Codelco. The next season, the club won the regular season and qualified to the promotion playoffs, but failed to win the group that consisted of 6 teams. In the 1987 season, with the defenders Gabriel Mendoza and Atilio Marchioni as key players, the club returned to the Primera División, after an exciting final with Lota Schwager at Talca.