The former aid worker also committed to giving the vanquished David Cunliffe a senior position in the party, despite the former finance spokesman pushing Mr Shearer hard for the party leadership.
Mr Shearer won the majority of votes from Labour's MPs, voting on the party's new leader this morning. He takes over from the outgoing Phil Goff.
Mr Shearer's deputy will be Grant Robertson.
The numbers in today's vote weren't revealed and the ballot papers have been destroyed.
"There's only one person in this room who knows the numbers and she's not telling," Mr Shearer said.
His priority in the first few weeks is to get out and talk to New Zealanders about how the party can reconnect with the county.
He wanted Labour to"come out of this process more energised and unified".
Mr Shearer also wants to work closely with other opposition parties, saying Labour has become "a little old-fashioned in its outlook".
Today's meeting began at 9.45, starting with a farewell for outgoing MPs Brendon Burns and Raymond Huo before Phil Goff presented his final report as leader.
Mr Shearer's camp yesterday reported that it had the numbers to take the vote with a few to spare after the final flurry of lobbying to try to secure the undecided MPs.
Two of the 34 MPs - Maryan Street and Charles Chauvel - had proxy votes because they are overseas.
The winner needed at least 18 votes and Mr Shearer's camp believed last night he had at least 20. However, he said was wary about MPs changing their minds or going against their promises in the privacy of the secret ballot.
- Amelia Romanos/Herald Online staff
