Miagao became an independent Municipality in 1716. It used to be a part or arrabal of four (4) different towns. Record shows that before Miagao became a town, it was an arrabal of Oton until 1580; of Tigbauan until 1952; of Suaraga or Suaragan (now San Joaquin) until 1703; and of Guimbal until 1716 when it became an independent town. It was until 1731, however, when Miagao had its own head. 
The first capitan and teniente mayor (equivalent to mayor and vice mayor in present day set-up) of Miagao were Nicolas Pangkug and Diego Sale, respectively. Their “election” was held in Guimbal under the supervision of Victorino C. Ma., authorized representative of the governor. Nicolas Pangkug served for three consecutive terms of one year each from 1731-1733.Before he became town capitan, Nicolas Pangkug was teniente mayor of Guimbal. As a resident of Miagao, he was entrusted with the care and supervision of this town until he became the head. Pangkug became capitan again in 1735 and 1739-1740. Altogether, he served for six years.

From 1716 to the present, Miagao has had 133 townheads with Julieta N. Flores, wife of former Municipal Mayor General Gerardo N. Flores (ret.), former Deputy Director General of the Philippine National Police, as the incumbent Municipal Mayor.

How Miagao got its name has several versions. The two popular ones, however, are on record. One popular version is that the name

Miagao was derived from the name of a wild plant called “MIAGAOS” that grew abundantly in the place when the Spaniards first came here.

Another version, according to Rev. Fr. Lorenzo Torres, a native priest of Igbaras, Iloilo, is that

Miagao was derived from the name of an old negrito called Miyagaw, who when asked of the name of the place by the Spaniards, gave his name instead. The Spaniards mistook the answer as the response to their query. A third version is a legend which relates that the name Miagao came from the love story of two young lovers, Maya and Gao.