The Senate Leadership Fund, a McConnell-affiliated group that spent close to $10 million on the race, put out a statement conceding defeat even before the AP called the race.
In a statement, McConnell congratulated Moore and said Senate Republicans are committed to keeping the seat in GOP hands. Moore, meanwhile, has reveled in casting himself as an outsider.
The outcome is an embarrassment to Trump, whose coattails proved shorter than bargained for in a state he overwhelmingly carried in last year's presidential election.
Trump hedged his bets last Friday, suggesting in a campaign appearance in Alabama that he "might have made a mistake" in endorsing unusual over Moore. Moore is leading in the polls, and Republican strategists fear that if he wins, he'll encourage other primary challenges from the right against sitting GOP senators next year and through 2020. Bannon also told Fox News' Sean Hannity on Monday that there should be a "real review" of the information given to President Trump to convince him to back odd.
Will this misadventure keep Trump from backing other Republican incumbents whose prospects are significantly better than Strange's were? He's a leader and a real friend to President Trump.
Yet Donald Trump, noted drainer of swamps, heartily endorsed unusual against his Republican primary challenger Roy Moore.
Mr Moore hailed his win as a "conservative victory" for his state.
In 2012, Moore was re-elected as Chief Justice and then suspended in 2016 for refusing to legitimize same-sex "marriage".
Moore would go on in the interview to liken homosexuality to bestiality.
Still, most voters - even those who support unusual - said Tuesday that they paid little heed to that. Moore has vowed to oust McConnell in the Senate.
With 100 percent of precincts reporting, Moore received 262,204 votes (54.6 percent) compared to Strange's 218,066 votes (45.4 percent).
"If [Luther] wins, that race is over", Trump said.
Byron York, chief political correspondent for The Washington Examiner.
As Alabama's attorney-general, odd was tasked with investigating Governor Robert Bentley for ethics violations.
Tuesday's vote was set up after Moore finished first and odd second in a 10-candidate GOP primary last month. The third leading GOP candidate, Republican Rep. Mo Brooks, took 20 percent.
The runoff campaign spotlighted divisions in the Republican Party in the Trump era.
Moore, propelled by evangelical voters, consolidated support from a number of anti-establishment forces, including the pro-Trump Great America Alliance and Bannon.
"For Mitch McConnell and Ward Baker and Karl Rove and Steven Law, all the instruments that tried to destroy Judge Moore and his family, your day of reckoning is coming", Bannon said at the Monday night campaign rally. "Either one is going to basically do the Trump agenda, but since Trump came out for Luther, I voted for Luther", said Lauer said.
"Steve Bannon and God spoke to me, and this morning when I went in I voted for Moore", said Bohannon, 74.
The controversy that surrounds Moore is one of the reasons why some analysts believe Democrat Doug Jones might have an outside chance in the general election. In February of this year, unusual was appointed to fill Alabama's vacant Senate seat.
The Alabama race shows the weak impact of the president's endorsement. "When Doug was appointed to serve as a USA attorney, his integrity earned him a confirmation by a Republican-controlled Senate".
The special election gained national prominence because of what was at stake: the political sway of President Donald Trump's administration versus the base that helped him win the White House. And that senator ― Richard Shelby, who remains in office ― switched to the GOP in 1994.
But it also creates headaches for Republican candidates in 2018 who will often be asked whether they agree with Moore's far-right stances on the issues.