On 10 July 2003, Pope John Paul II appointed him a coadjutor bishop for the Diocese of Rancagua—a coadjutor bishop performs the same functions as an auxiliary bishop, but is entitled to succession when the office becomes vacant. Thus, with the resignation of Bishop Javier Prado Aránguiz (for reasons of age), Goic took over as the ordinary bishop of the Diocese of Rancagua. He held that post starting in 2004, and is also the President of the Chilean Conference of Bishops. In 2007, Goic was approved for three years in that office. Pope Francis accepted his resignation on 28 June 2018. Social role One of the main concerns of Goic's years as a priest has been social issues. His special sensitivity to the issues of poverty and social justice originate with a deep identification with the sufferings of Jesus Christ and the principles of the Gospel. Workers' rights During the 1980s, when Goic was auxiliary bishop of the Archdiocese of Concepción, he decided to visit Father Enrique Moreno Laval, a vicar in the Lota coal mining area, in order to familiarize himself with the situation of native workers demanding labor improvements. In turn, he received complaints from unionists in the military regime, who gave him the epithet "Bishop Red". Goic, however, has never been afraid of reprisals, although on one occasion recordings of the radio program Testimonio—which documents human rights and labor abuses—were seized by the military. 2006 student protests Although not a formal mediator between the warring parties of the 2006 student demonstrations, Goic repeatedly expressed his desire that the demonstrations reach a successful conclusion. Goic issued a statement expressing his opinion: There isn't anyone in Chile that doesn't want to improve the quality and equity of education here. One would like to ask the student leaders, who have proven very competent, that they have a little patience, so that [this issue] may be worked through in the parliament. On 25 May 2006, a group of students threw stones at Goic's residence in the city of Rancagua, having done the same to the city's Liceo Oscar Castro. The bishop had expressed his intention to mediate only hours before. Labor outsourcing In his capacity as Bishop of Rancagua, Goic was a key factor in the 2007 negotiations between conflicting parties in a fight over Codelco's outsourcing of workers. In a letter signed by him as President of the Chilean Conference