Mr Farage clinched a victory with 21,225 votes, taking the seat from the Conservatives who came second with 12,820 votes.
Speaking after the result, he said: “I think what Reform UK has achieved in just a few short weeks is truly extraordinary.”
He added: “There’s no enthusiasm for Labour whatsoever. This Labour government will be in trouble – very, very quickly. We’re coming for Labour, be in no doubt about that.
“This is just the first step of something that’s going to stun all of you.”
Earlier, former Tory MP Lee Anderson became Reform’s first elected MP when he was re-elected in his Ashfield seat, after previously defecting from the Tories.
Mr Anderson was the deputy Conservative Party chairman under Rishi Sunak but was sacked earlier this year following a row over comments he made about London Mayor Sadiq Khan.
Mr Anderson won the seat comfortably, gaining 17,062 votes compared to 11,553 for Labour, who came in second.
In an even further blow to the Conservatives, they came in fourth behind an independent.
In what is shaping up to be a good night for Reform UK, former party leader Richard Tice has also won in Boston and Skegness.
And Rupert Lowe also won for Reform in Great Yarmouth. He picked up 14,328 votes, compared to 12,959 for Labour’s Keir Cozens in second, and 10,034 for Conservative candidate James Clark in third.
The party looks set to establish further footholds in parliament, with the general election exit poll projecting it would win 13 seats.
However, some forecasts as the night went on suggested Reform may not gain as many seats as the exit poll indicated.
In areas where it has not won, Reform looks to have eaten into the Conservatives’ share of the vote, pushing them into third place across the North East and even fourth in Gateshead Central & Whickham.
Welcoming the signs of promise for his party, Mr Farage earlier said on X: “It’s midnight, there are two results in from the northeast of England that put Reform on 30% of the vote, that is way more than any possible prediction or projection. It is almost unbelievable.
“And what does it mean? It means we’re going to win seats – many, many seats I think – right now across the country.”
He added: “This is going to be six million votes plus. This folks is huge.”
The clip was captioned: “The revolt against the establishment is under way.”
Mr Farage’s ultimate aim is to make Reform the official opposition to Labour, who are projected to win this election by a landslide.
Sir Keir Starmer’s party looks set to secure the win with an estimated 410 seats – equating to an overall majority of 170 – according to the poll by Ipsos UK for Sky News/BBC/ITV News.
Meanwhile, the Conservatives are projected to win just 131 seats, compared to 365 in the 2019 vote, which could be the party’s lowest seat total in its modern history.
The wipeout has seen some of the Tories’ most senior figures lose their seats, including Defence Secretary Grant Shapps, Commons Leader Penny Mordaunt and Veterans Minister Johnny Mercer.
The success of Reform is likely to play a huge role in the future direction of the Tory party.