Cesar Buenaventura was the son of fine arts professor Teodoro Buenaventura and Agripina Espinosa. He attended San Beda College and worked as an illustrator in various commercial firms before World War II. His greatest artistic mentor, was Fernando Amorsolo, for whom Buenaventura became a "mantsador". Buenaventura later became the biggest influence in the Mabini art scene.
A very versatile impressionist painter, he infused his distinct mark in traditional countryside scenes, seascapes and market settings. Like Amorsolo, he was partial to subdued tones. One of Buenaventura’s paintings won first place in national art contest sponsored by Far Eastern University in 1950. He exhibited at the Carnegie Endowment Center in Washington, DC and New York and De La Rama Steamship Co. His paintings can be found at the Art Gallery of University of Thomas and in private collection worldwide.