Curt Clawson of Bonita Springs won 38 percent of the vote Tuesday in the district, which includes a strip of Florida's southwest coast from Marco Island to Fort Myers. He spent more than $3 million of his own money.
"I got into this race because I felt like we needed more outsiders in Congress," Clawson tweeted after the results were in. "The career politicians aren't getting the job done."
The district had been represented by freshman Trey Radel. He resigned in January after pleading guilty to a misdemeanor drug charge after buying cocaine from an undercover Washington police officer.
Clawson is believed to have a good chance of defeating the Democratic candidate, April Freeman, on June 24. The seat will also be up for grabs in November.
On Monday, the Tea Party Express called the primary "first tea party vs. establishment showdown" of the election year. The runners-up were state Sen. Lizbeth Benacquisto and former state Rep. Paige Kreegel.