Ardern was born in Hamilton and grew up in Morrinsville and Murupara. After graduating from the University of Waikato in 2001, Ardern began her career working as a researcher for Prime Minister Helen Clark. She later worked in London in the Cabinet Office, and was elected president of the International Union of Socialist Youth. Ardern was first elected as an MP in the 2008 general election, when Labour lost control after nine years. She was later elected to represent the Mount Albert electorate in a by-election in February 2017.