Mata'afa was born in 1921, the son of Paramount Chief Mata'afa Faumuina Fiame Mulinu'u I. He was educated at the Marist Brothers school in Apia. He married Laulu Fetauimalemau Mata'afa, a teacher educated in New Zealand and who later became Samoa's High Commissioner (1993–1997) to New Zealand. He was bestowed with the Fiame title in 1948, and also became a Faumuina. When his father died in 1948, he acceded to the Mata'afa title. He was a senior grade rugby player and President of the Western Samoan Boys' Brigade.