He was born in Patras in 1760, to a wealthy family of Sicilian descent. His father was Benizelos Rouphos (elder). Kanakaris was elected as a headsman of Patras in 1785, and became one of the most influential Greek magnates in the Morea. While serving as the province's representative to the Porte, he became a member of the Filiki Eteria. During the Greek War of Independence, he served as a member of the Peloponnesian Senate and of the First National Assembly at Epidaurus, and contributed from his personal fortune to the Greek cause. From 13 January 1822 to his death of illness in 1823, he served as deputy president of the Executive Corps of the Greek provisional government, under Alexandros Mavrokordatos.
His son was also called Benizelos Rouphos and served as Prime Minister of Greece later on. Other members of the family served as mayors, members of parliament and ministers. He married Paraskevi Kostaki and apart from the aforementioned son they had a daughter called Aggeliki.