Sin was ordained to be Auxiliary Bishop of Jaro in 1967. He became the Apostolic Administrator of the Jaro diocese in 1970 and was appointed the Metropolitan Archbishop of Jaro in 1972. In 1974, Pope John Paul VI appointed Jaime L. Sin to become the new Archbishop of Manila and appointed him as a Cardinal that same year. The young Cardinal Sin was faced with two extraordinary tasks in his new post. First, he had to lead the Filipino Church in implementing the directives of the Second Vatican Council. This was no easy task as it involved an overhaul of the Church’s pastoral and liturgical practices, including a shift from Latin to the various Filipino languages. Second, the country was in the early years of martial law and the Catholic Church was struggling to organize itself in defense of freedom and human rights. Cardinal Sin was quite ready to handle these challenges.

By the late 1970’s the shortcomings of the regime were becoming obvious. Many Filipinos began to take to the "parliament of the streets." Others, including some Catholic religious and clergy, took to the mountains in support of the armed struggle for liberation. The period was difficult for the Filipino people and, of course, for Cardinal Sin. In 1971, the World Synod of Bishops reminded the entire Catholic Church that action for justice must be an integral part of the mission of the Church. Meeting in Manila in 1971, the Federation of Asian Bishops Conferences declared that in the Asian context, the Church should become a "Church of the Poor." Cardinal Sin won the admiration and respect of the Manila Church and its clergy, especially after he was elected to be the president of the Catholic Bishops’ Conference of the Philippines (CBCP). His policy of "critical collaboration" became the vision of the CBCP’s engagement in the struggle for justice.

With the assassination of Senator Benigno "Ninoy" Aquino in 1983, Cardinal Sin took a direct role in politics, even convincing C. Aquino, the one person who appeared to have a chance against the incumbent, to run in the snap presidential elections of January, 1986. The election count appeared fraudulent to the Filipino masses and in February, Cardinal Sin appealed to the people to take to the streets in what would later be called the "Miracle of EDSA." Fifteen years later, in 2001, Cardinal Sin encouraged people to go once again to EDSA. In EDSA II, the diocesan priests of Manila said Cardinal Sin was a "prophet" whom they gladly followed. The Filipino masses apparently agreed.

Perhaps the best tribute Filipinos can pay to the Cardinal is to renew their dedication to the task of reforming the Church and the nation along the paths of justice, love, and peace. Cardinal Sin has given his best to the Catholic Church and to the country.

Happy Anniversary to His Eminence, Jaime L. Cardinal Sin! The nation has not forgotten.