Who is Andrew Little? The union chief and Gangnam Style dancer who became leader

Andrew Little, who was today elected leader of the Labour Party, is a lawyer and high-profile union leader who has risen quickly through Labour's ranks.

Before he entered Parliament in 2011, Mr Little, 49, was the head of the Engineering, Printing and Manufacturing Union (EPMU) for 11 years.

Raised in New Plymouth, he studied law at Victoria University, where he became student union president, and later president of the New Zealand University Students Association.

His first job was as a solicitor for the Engineers Union (later EPMU), working on employment law and ACC issues.

He rose through the ranks at the union, eventually becoming national secretary, and helped the organisation grow into one of the largest in the country with around 40,000 members.

After Labour's 2008 election defeat, Mr Little became party president.

He ran for Parliament in the New Plymouth seat out of concern about the erosion of workers' rights, such as National's introduction of the 90-day probation law.

Elected on the list in 2011, he was not expected to remain on Labour's backbenches for long.

He gained some profile as the party's ACC spokesman when the corporation went through significant changes under National.

His attacks on then-minister Judith Collins during a mass privacy breach at ACC prompted the minister to take defamation action against him. He and Trevor Mallard had accused Mrs Collins of leaking an email, but the case was settled out of court.

Mr Little moved up Labour's list in a caucus reshuffle in 2013 and took on the justice and labour portfolios.

Little tweeted this picture of himself and his cat during the leadership campaign. Photo / Twitter

In another reshuffle early this year, former leader David Cunliffe promoted him a further six places to number 11 because of the "heavy lifting" he had done in those portfolios.

Mr Little lobbied for a reversal of legal aid cuts, and sought the introduction of corporate manslaughter laws to increase accountability in cases such as the Pike River disaster.

He helped develop new policy which improved the rights of sexual assault victims and reversed the burden of proof in rape cases, though the policy's release was overshadowed by Mr Cunliffe's "sorry for being a man" speech.

Mr Little also won attention for performing the Gangnam Style dance in the House while accusing National of "riding the invisible horse of decision-making".

He has struggled to win over voters in his New Plymouth electorate, losing by 4000 votes in 2011 and 10,000 votes in 2014, though the second defeat was partly blamed on unfavourable boundary changes.

That meant he scraped into Parliament on the list in September, and had a nervous wait as special votes were counted.

When his re-election for a second term was confirmed, he put his hand up for leadership, nominated by Poto Williams and Iain Lees-Galloway.

He campaigned on a platform of restoring faith with votes and unifying the caucus. Unlike many of Labour's MPs, Mr Little was not easily lumped into one of the party's factions.

He also promised to review unpopular policies such as a capital gains tax and raising the retirement age.

Mr Little is married and lives in Island Bay, Wellington, with his wife and son.