On 21 April 1955, the Asociación Central de Football decided that the team will play in the Primera División for the next season, with the first president being Nicolás Abumohor and the first head coach being Francisco Hormazábal.

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.

[2] 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 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.

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.

However, in the final against Colo-Colo, the club lost on penalties, whilst for the Primera División tournament, the Rancaguan side finished in the third place of the table, therefore missing out on achieving Copa Libertadores qualification.

[4] In the 1996 season, the club signed great players, such as midfielder Clarence Acuña, Argentine playmaker Gerardo Martino, and strikers Carlos Poblete and Ariel Cozzoni.

[6] In 1999, the Rancagua club finished in tenth place, in which Mario Núñez and Jaime González also became the most successful goalscorer pair in Chilean football with 57 goals between both strikers.

[1] He brought in manager Gerardo Silva as Cossio's replacement, and the club eventually achieved that long awaited objective, defeating Deportes Melipilla 4–3 on aggregate for the promotion with Hugo Brizuela and Mario Núñez as the key players of the success.

[9] The next season, the club signed Jorge Garcés as coach, qualifying for the playoffs of the Torneo Clausura, where they beat Coquimbo Unido in the quarter finals and were eliminated by Audax Italiano in the semi-finals with controversial decisions made by referee Rubén Selman.

Sampaoli had a successful season during the Apertura 2008, with talented players like Jean Beausejour and Carlos Carmona, finishing third in the league table but being eliminated in the playoff quarter-finals by Universidad de Chile.

Hernandez brought the team into the top 5 places into the table during the first half of the season, but after the FIFA World Cup break he started to have poor results, so he was fired and Marco Antonio Figueroa arrived as a replacement.

[10] The year started of abrupt form with Fernando De la Fuente's departure after a strong discussion with new head coach Berizzo and his assistant, Roberto Bonano.

[17] Despite this loss, the team achieved four consecutive wins, with Julio Barroso and Rodrigo Rojas as the key players, a run that finished when Huachipato defeated the club 2–1 on 15 April.

[22] In the first match at La Calera on 24 May, the team won 1–0 with a free kick scored by Ramón Fernández, who did not celebrate the goal as he was planning to leave the club at the conclusion of the season.

[27] In the second leg on 2 July, played at the Estadio Nacional, the scoreline was 1–1 which put O'Higgins up 3–2 on aggregate, and was about to win their first league title by becoming Torneo de Apertura champions, until the 92nd minute, because with Guillermo Marino's goal the series was equalized at 3–3 and the match went to penalties.

On the next match day, the club tied with Audax Italiano but after that they team went on a significant winning streak, which began by beating Cobresal in El Salvador, and then Cobreloa, Universidad de Concepción, Universidad Católica, Unión Española and a victory over Unión La Calera in the final minutes, with the club only losing two games against Palestino and Colo-Colo. On 7 December 2013, the last match day of the championship, the club has to visit Rangers de Talca, where the team starts losing with a Mauricio Gómez goal, but the team did not give up and turned the game around in their favor with a penalty from Pablo Calandria and a goal from Julio Barroso.

O'Higgins won 3–2 after Rodrigo Brito of Deportes Iquique missed his penalty, unleashing the joy of over 6,000 celeste fans who came to the Santiago Metropolitan Region, and becoming the second Superchampion of Chilean football.

After becoming Chile's super champion, Eduardo Berizzo leaves the institution and joins Celta de Vigo in Spain, thus ending the most successful seasons in the club's history.

For the Apertura 2014 the new light blue coach is Facundo Sava, players like Luis Valenzuela arrive after his time at Deportes Antofagasta, Hans Martínez who came without regularity from Almería, the Uruguayan Octavio Rivero, who came to replace the scorer Pablo Calandria who was not registered in the tournament due to a meniscus injury, and the trans-Andean Jorge Carranza, Damián Lizio and Fernando Elizari in that championship began with a 2-1 victory over Unión La Calera, then on the following date they lost against the University of Chile in Rancagua .

In the 2015 Clausura, after the dismissal of Facundo Sava, Vitamina Sánchez took over the team, Hugo Droguett, who came from South Korea, and Sebastián Pinto, who returned to the institution after passing in 2011, joined the squad.

The second part of the year in the 2015 Apertura, the team is reinforced with; Esteban González from Huachipato and a historic one like Yerson Opazo leaves for the plant institution, Pedro Muñoz from the Universidad de Concepción, Emilio Zelaya from Arsenal de Sarandí and the returns of Gonzalo Barriga who came from a loan at Santiago Wanderers, and Ramón Fernández, Hans Martínez was fired from the club, Sebastián Pinto goes to Eskişehirspor, César Fuentes is bought by Universidad Católica and Alejandro López leaves for Cobresal.

The 2017 started with a failed participation in the 2017 Copa Sudamericana, facing the Ecuadorian Fuerza Amarilla, losing in the agreggated 2-1, playing his away game at the Estadio George Capwell.

The team takes a boost in the final stretch of 2018 season led by Marco Antonio Figueroa, finishing eighth, but out of international competitions, also marking the retirement of sky-blue scorer Pablo Calandria, who scored at his last game a penalty against Audax Italiano.

Another important player of the club is Pablo Hernández, also Argentine, who was part of the historic squad led by Eduardo Berizzo that won the 2013–14 Torneo de Apertura.

He was one of the most important players of the team, alongside the goalkeepers Paulo Garcés and Roberto González, the defenders Julio Barroso, Mariano Uglessich and Yerson Opazo, the midfielders Luis Pedro Figueroa, César Fuentes, Braulio Leal, Gonzalo Barriga and the striker and top goalscorer Pablo Calandria, among others.

Juan Rodrigo Rojas, now playing in Cerro Porteño, and Octavio Rivero, who was signed by Vancouver Whitecaps of Major League Soccer for a US$1.5M fee, were the last players of Paraguayan and Uruguayan nationality, respectively.

Several Rancaguan people affirm that the phoenix represents the Chilean historic city, in where the founding father and hero of the country, Bernardo O'Higgins, led his army to win the Battle of Rancagua against Spain, highlighting that the club's name is in honour of him.

The author was a young man from Rancagua named Miguel Ángel León Morales, who, in addition to being a fan of the team, left his mark by writing the lyrics.

Among its lyrics was created the mythical O'Hi-O'Hi, Ra-Ra!, a battle cry that since then has been heard by its fans in the stands of all the stadiums in Chile and in international competitions where the team participates.