John Fetterman, the Democratic lieutenant governor of Pennsylvania, will defeat Mehmet Oz, the Republican senate candidate, in a race that will determine control of the upper chamber of congress.
According to NBC, Fetterman had a margin of about 66,000 votes.
The Republican-held Senate seat will be taken over by the Democrats.
The Democrats were hoping to flip the seat in a key swing state where President Joe Biden defeated Donald Trump two years earlier.
Another blow to Trump was dealt by the projected verdict, as he supported Oz in the GOP primary.
It is officially done. Fetterman said he would be the next senator from Pennsylvania.
Fetterman said that the people of Pennsylvania didn't let them down.
After a stroke took the Democratic nominee off the trail for three months, Oz, a celebrity doctor who had invested millions of dollars of his own money in his first campaign for elected office, trailed Fetterman in the polls.
A wealthy TV host who lived in New Jersey until a year before launching his campaign was accused of being an out-of-touch carpetbagger.
Fetterman's campaign slammed Oz for complaining about the price of vegetables for a "crudites" platter and for owning a lot of properties.
Oz made gains in the final weeks of the race, as his campaign bombarded Fetterman with accusations that he was too far left for Pennsylvania. Oz had high unfavorability ratings going into election day.
Oz told a crowd of his supporters that he would win the race when all the votes were counted.
A spokeswoman for Oz didn't reply to CNBC's request for comment on NBC's projection
I'm overwhelmed. Fetterman thanked the crowd in his speech.
He said that the campaign was launched almost two years ago and that the slogan is on every sign in the country. That's what happened. We were able to jam them up.
Fetterman had a life threatening stroke just before he won the Democratic primary. Oz and his allies questioned whether Fetterman was healthy enough to serve in the Senate after he suffered a stroke.
Fetterman's doctor said he expected the lieutenant governor to be able to work without restrictions, even though he is having problems with hearing. Fetterman's health challenges were on full display during his one debate with Oz, when he showed great difficulty forming complete sentences and providing full responses.
Fetterman said at the end of the debate that his campaign was all about fighting for people who had been knocked down and had to get up again.