In the Canberra parliament's final session of the year on Thursday, lawmakers engaged in a lengthy debate as several amendments put forward by opponents of the bill to legalize same-sex marriage were voted down.
The House vote took place on the last sitting day of parliament for the year, with more than 100 MPs speaking on the bill this week.
Just four members voted against the bill.
"We've voted today for equality, for love, it's time for more marriages, more commitment, more love, more respect", Prime Minister Malcolm Turnbull said. "Marriage equality is finally the law of the land and it's time to start celebrating".
Additionally, the passing of the same-sex marriage law will be a strategic political win for Turnbull, who has been strongly opposed by his predecessor Tony Abbott, a staunch supporter of conventional marriage.
The public gallery burst into an impromptu rendition of We Are Australian immediately after the bill passed.More news: Willie Taggart coming back to Florida to coach FSU
Many Australians took to Twitter to post a video of their TV screens as the bill was passed - and various videos of LGBT+ Australians reacting to the news cropped up on the platform. "Every Australian had their say, and they said it is fair, get on with it!"
Under current legislation in the states and territories, with the exception of South Australia and the ACT, if a married man and woman become, for example, a woman and woman, the state can refuse to alter the birth certificate for the partner who has changed gender. "At long last, LGBTIQ Australians will be equal under the law".
Australia joins about two dozen countries around the world, including Germany, which have legalized same-sex marriage.
The next day, Liberal MP Andrew Wallace, who is a devout Catholic, shared with his colleagues how his gay daughter helped change his position on same-sex marriage.
The move follows a two-month national postal survey that showed 61% of more than 12 million respondents were in favor of marriage equality.