Atty. Fruto obtained his Bachelor of Laws degree in 1961 from the Ateneo de Manila University, and was admitted to the Philippine Bar on February 22, 1962.

Formerly, he was a partner in the law firm of Feria, Feria, Lugtu & La O' and the Oben, Fruto & Ventura Law Office and a professor of law in the Ateneo de Manila University and the Lyceum of the Philippines.

Aside from specializing in corporate law, he handled trial and litigation work before the Metropolitan Trial Courts, Regional Trial Courts, the Sandiganbayan, the then Juvenile & Domestic Relations Court, the then Court of Industrial Relations, the then Land Transportation Commission, Labor Arbiters, administrative bodies like the Securities and Exchange Commission, covering civil cases (contracts, commercial transactions, maritime, estate, family relations, transportation, and other civil cases), labor cases and administrative proceedings.