On January 24, 1991, Davide was appointed by then-President Aquino as Associate Justice of the Supreme Court. From January 2, 1996 to August 30, 1997, he sat as a member of the Senate Electoral Tribunal. He was also the Working Chairman of the Court’s Third Division from January 2, 1996 to September 7, 1997, and Chairman of the House of Representative Electoral Tribunal from September 1, 1997 to November 30, 1998.

On November 30, 1998, he was appointed by President Joseph Estrada as the 20th Chief Justice of the Philippines. He took his oath of office at the new Bonifacio Shrine in the City of Manila. He became known as the Centennial and Millennial Chief Justice.

He was the presiding judge in the impeachment trial against then-President Estrada in December 2000. When the popular protests spilled into the streets, his timely intervention on behalf of “the welfare and will of the people” by administering the oath of office as President to then-Vice-President Gloria Macapagal-Arroyo. By declaring her the constitutional successor it averted potential violence and military takeover of power, and brought the crisis to an end. Although the moral authority of the Supreme Court carried the day, Davide’s action was further bolstered by a precedent setting Supreme Court decision, effectively putting an end to the question of the legitimacy of Vice-President Arroyo’s succession to power.[citation needed]

Davide retired as chief magistrate on December 20, 2005 after he reached the mandatory retirement age of 70.

However, on January 24, 2006, President Arroyo appointed him as Senior Presidential Adviser on Electoral Reforms during a Council of State meeting convened by the President. He recommended measures and policies to the President that would help reform the country’s electoral system