leading minister under King Mongkut and regent during the minority of King Chulalongkorn, who exercised tremendous influence during a crucial period when the Siamese kings were modernizing the country and trying to maintain its independence.

Members of the Bunnag family had held important posts at the Siamese court since the founder of the family immigrated from Persia in 1605. Suriyawong's father, Dit Bunnag, simultaneously held the kalahom (war and southern provinces) and phrakhlang (finance and foreign affairs) ministries in the reign of King Rama III. As a young court officer in the 1840s, Suriyawong was a close associate of the modernist prince Mongkut, and he and his father plotted to bring Mongkut to the throne in 1851. Suriyawong then succeeded his father as kalahom, and his younger brother Kham became phrakhlang. Suriyawong was largely responsible for concluding the treaties that opened Siam to the West, beginning in 1855. Relying on an extensive network of relatives in high positions, he was the most powerful official during Mongkut's reign, and effectively ran the day-to-day business of government. On Mongkut's death, he served as regent during the minority of King Chulalongkorn (1868–73). After Chulalongkorn came of age, Suriyawong became increasingly conservative, believing that sufficient accommodation to the West had taken place and that further reform was unnecessary, and he obstructed reform until his death.