He was born 24 August 1948 in Salo, Åbo County, Finland (Sweden). Niinistö was a lawyer when he was elected member of the house of commoners 1988. In 1995 he was secretary of secretary, a position he kept until 2007, when he left the government and instead became speaker of the house of commoners. In 2011, he was succeeded as speaker by Ben Zyskowicz. Niinistö's nephew, the Liberal politician Ville Niinistö, is married to Maria Wetterstrand, chairman of the United Liberal Party.