Former Supreme Court Chief Justice Reynato Puno has been invited by the Senate impeachment court, as he was included among the legal experts tapped by the court to provide legal advice on the voting threshold in the impeachment trial of Vice President Sara Duterte.

Puno graduated with a Bachelor of Science in Jurisprudence, followed by a Bachelor of Laws from the University of the Philippines. He also pursued his postgraduate degrees abroad, earning a Master of Comparative Laws from Southern Methodist University and a Master of Laws from the University of California, followed by a Doctor of Juridical Science from the University of Illinois.

The retired chief justice built an extensive career in private law practice, legal education, public offices, and four decades of service in the Philippine judiciary.

Puno began his legal career in 1962 as an Assistant Attorney in Gerardo Roxas and Abraham F. Sarmiento Law Office. The following year, he entered public service as a Tax Attorney for the Joint Legislative and Executive Tax Commission until 1967.

Alongside his service in the government, Puno served as a Professor of Law at Far Eastern University from 1969 to 1973. Besides, the former chief justice also served as a lecturer in the U.P. Law Center - Institute of Judicial Administration and a special lecturer in Constitutional Law at the Philippine Judicial Academy.

In 1971, he joined the Office of the Solicitor General (OSG) as a solicitor. In 1974, Puno was promoted to Assistant Solicitor General in 1974, serving in the position for eight years.

He was appointed Associate Justice of the Court of Appeals from 1980 to 1984. During his period in the executive branch, he also served as Acting Chairman of the Board of Pardons and Parole in February 1985.

Puno returned to the Court of Appeals as Associate Justice on August 1, 1986. He also continued to apply his legal expertise to legal education, serving as a Bar Examiner in Mercantile Law in 1989 and in Taxation in 1993.

On July 6, 1993, Puno was appointed to the Supreme Court as Associate Justice and served for 13 years, and was subsequently promoted to Chief Justice on December 7, 2006, until May 16, 2010.

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