It consists of twenty-five members elected from an equal number of constituent districts across the islands and is led by the President of the Senate, elected from the membership of the body, currently Ron Kouchi.

In 1894, the Constitution of the Republic of Hawaii renamed the upper house the present senate.

From 2016 (when Sen. Sam Slom, Hawaii's sole Republican state Senator, was defeated in his bid for reelection) to 2018, the Democratic Party held all 25 seats in the Hawaii Senate.

This made the Hawaii Senate the only state legislative chamber with no opposition members (this excludes the officially nonpartisan Nebraska Legislature).

Previous to the decision of Governor John A. Burns to build the new Capitol building, the Hawaiʻi State Senate met in ʻIolani Palace.