Wearing a glittering, rainbow-coloured coat, the Taupo-born Maori who came out as gay aged 21 thanked her "darling" partner Prue Kapua, who watched from the full public gallery.
"Nothing can counteract the very real negative consequences of not passing this bill. But nothing could make me more proud to be a New Zealander than passing this bill," Ms Wall said.
"I thank my colleagues for simply doing what is just, fair and right."
In the end, her bill passed into law without rancour. Rain kept protesters away from Parliament, and many opponents had conceded defeat weeks ago and said they wouldn't fight any more.
Few of the opponents of the bill chose to speak during the debate.
National MP Jonathan Young, whose father Venn Young attempted to decriminalise homosexuality 37 years ago, argued that it was impossible to legislate for love.
He said he supported civil unions, but that was because they did not affect the tradition of marriage.
"A tradition is the institutional memory of a society. It is not to be ... cast away quickly or easily."
The bill's impact would reverberate beyond marriage, the House was told. Ms Wall spoke of a gay mother whose partner had to have her name struck off her daughter's birth certificate when she died, because only one person in a gay relationship could be recognised as a parent or guardian.
The Marriage (Definition of Marriage) Amendment Bill would allow both people to be legally recognised as a parent of an adopted child.
But the historic night was mostly one of celebration. Green MP Kevin Hague, a campaigner for gay rights for 30 years, opened his call at Parliament by declaring: "It's time."
He spoke of his relationship of 28 years, but also with rare contempt for some of the groups who he felt had infected the debate with extremism, threats and blackmail.
"There is no longer any room for any nuance or middle ground. Instead, what history will record is whether you voted for inclusiveness, equality under the law and pluralism, or against them."
Of the six openly gay MPs, all but National Cabinet minister Chris Finlayson voted for the bill.
Like National MPs Paul Hutchison in the first reading and Chris Auchinvole in the second reading, Cabinet minister Maurice Williamson stole the show with a joke-filled speech.
"One of the messages I had was that this bill was the cause of our drought. Well ... in the Pakuranga electorate this morning, it was pouring with rain, we had the most enormous big gay rainbow across my electorate. It has to be a sign."
The bill was voted on conscience, not along party lines. Nearly half of National Party and all but three Labour MPs backed the change.
In August, gay and transgender couples will begin saying "I do".
Marriage Amendment Bill
Takes effect mid-August
Allows same-sex and transgender couples to marry
Allows both people in a gay relationship to be recognised as a parent of an adopted child
Allows religious ministers to choose who they marry and criticise gay marriage from the pulpit without breaching human rights
People getting married will be able to choose whether they are called a bride, bridegroom, or partner
