With most of the results in, he had more votes than his nearest two competitors—U.S. Representative Vicky Hartzler and scandal-ridden former Missouri Governor Eric Greitens—combined.
McCloskey, meanwhile, trailed in fifth place with just 3 percent of the vote.
In November, Schmitt will be opposed by beer heiress Trudy Busch Valentine, who defeated Marine veteran Lucas Kunce and nine others in the Democratic primary.
"Apparently Donald Trump's endorsed all three of them," McCloskey said in a video posted on Twitter.
McCloskey and his wife, Patricia, gained national attention after they waved guns at protesters near their St. Louis home on June 28, 2020.
The couple were praised by Trump and other conservatives, and they spoke during the opening night speech at the 2020 Republican Convention.
In February, the Missouri Supreme Court put the couple on probation but allowed them to continue practicing law for another year. »