Samoa's first Prime Minister was Fiame Mata'afa Faumuina Mulinu’u II, one of the four highest-ranking paramount chiefs in the country. Two other paramount chiefs at the time of independence were appointed joint heads of state for life. 

Tupua Tamasese Mea'ole died in 1963, leaving Malietoa Tanumafili II sole head of state until his death on 11 May 2007, upon which Samoa changed from a constitutional monarchy to a parliamentary republic de facto.[45] The next Head of State, Tuiatua Tupua Tamasese Efi, was elected by the legislature on 17 June 2007 for a fixed five-year term.

The unicameral legislature (Fono) consists of 49 members serving 5-year terms. Forty-seven are matai title holders elected from territorial districts by Samoans; the other two are chosen by non-Samoans with no chiefly affiliation on separate electoral rolls.[47] Universal suffrage was extended in 1990, but only chiefs (matai) may stand for election to the Samoan seats. 

There are more than 25,000 matais in the country, about 5% of whom are women.[48] The prime minister is chosen by a majority in the Fono and is appointed by the head of state to form a government. The prime minister's choices for the 12 cabinet positions are appointed by the head of state, subject to the continuing confidence of the Fono.

Prominent women in Samoan politics include the late Laulu Fetauimalemau Mata'afa (1928–2007) from Lotofaga constituency, the wife of Samoa's first prime minister. Their daughter Fiame Naomi Mata'afa is a paramount chief and a long-serving senior member of cabinet. 

Other women in politics include Samoan scholar and eminent professor Aiono Fanaafi Le Tagaloa, orator-chief Matatumua Maimoana and Safuneitu'uga Pa'aga Neri, the current Minister of Communication and Technology.

The judicial system is based on English common law and local customs. The Supreme Court of Samoa is the court of highest jurisdiction. Its chief justice is appointed by the head of state upon the recommendation of the prime minister.