On 1 April 1908 the village of Kametsu was founded with the creation of the modern municipalities system.

On 1 April 1958, Kametsu merged with the neighboring village of Higashi-Amagi, and was renamed Tokunoshima.

Tokushima has a mayor-council form of government with a directly elected mayor and a unicameral town council of 14 members.

Tokushima, collectively with the other municipalities of Oshima District, contributes two members to the Kagoshima Prefectural Assembly.

In terms of national politics, the town is part of the Kagoshima 2nd district of the lower house of the Diet of Japan.