King, by all accounts, has been an ideal back-room deputy, experienced, respected and loyal to the leader. But she could not add much lustre to Labour's public performance, although she has been a feisty opponent for Steven Joyce in their regular joust on Newstalk ZB's Hosking Breakfast.
She did not take kindly to the suggestion last weekend that she should step aside for a younger woman. But on Wednesday, after a "chat" with Little, that is what she did. She also decided to retire when Parliament rises for this year's election.
King has been a highly regarded minister in two Labour governments spanning the past 32 years.
As a junior minister in the Lange Government she was a reputed stalwart of its economic reforms but Helen Clark, who was not, nevertheless gave King the sensitive and high-ranking health portfolio in her Government.
Few MPs will leave Parliament more well-liked and respected on all sides of the House.
But her replacement also leaves Labour looking fresher. She, Phil Goff and David Cunliffe were the last surviving familiar faces from previous governments and their departures allow the party to put a completely new crew in the cockpit.
It probably will not matter that Little has been leader for two years and that Ardern and Robertson have been in Parliament for longer than Little. They will be untried candidates for the country's most powerful positions when we come to the election.
Ardern's promotion will ask more of her than she has shown the public so far. She will not be elected deputy to be a loyal caucus go-between for the leader.
He will need her out front with him, balancing his image, enlivening his somewhat wooden presentations, using her social skills in situations where she appears more at ease than him.
But she must show she has substance too. That does not mean talking social policy jargon. It means dealing with problems and presenting solutions in the light of real life experience, as National's deputy Paula Bennett does. Theirs will be an interesting contest.
