Prime Minister Malcolm Turnbull, a long-time supporter of same-sex marriage was ecstatic and said this was a key moment in Australian social reform.
The bill cleared the upper house last month and had been expected to pass on Thursday after Turnbull's Liberal-National coalition government and the main opposition Labor Party had previously said they wanted to pass it by December 7.
Australia on Thursday became the 26th nation to legalise same-sex marriage, following a postal survey in which Australians overwhelmingly voted in support of formalising the unions.
Though the bill was expected to pass into law without significant opposition, the lengthy legislative process was excruciatingly slow for the hundreds of advocates watching from the public gallery.
"It's a historic day for Australia today and I think the celebrations around the country when we finally ... achieve marriage equality are going to be enormous", Greens party senator Janet Rice said.
It's time for more marriages.
John Mayer Hospitalized for Emergency Appendectomy
A publicist for the 40-yeaar-old said in a statement Wednesday that Mayer is recovering and "is in good spirits". Mayer has additional solo tour dates slated for this month, and it's unclear now how they'll be affected.
News.com.au reports that Christian couple Nick and Sarah Jensen have been hedging on their pledge to divorce in the wake of same-sex marriage becoming legal in Australia.
The Jensens first said they'd get divorced if same-sex couples could get married back in 2015.
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.
Almost eight out of 10 eligible voters participated in the survey, according to the government.
Lawmakers, who had cast aside a conservative push to allow religious objectors to refuse service to same-sex couples, waved rainbow flags and embraced in parliament, where earlier in the debate a politician had proposed to his same-sex partner. Simply and fairly, #MarriageEquality is now law!
The laws, which will also recognize same-sex marriages solemnized in foreign countries, take effect from Saturday. It was most recently authorised on Tuesday by Austria's top court by 2019 at the latest.