Mr McCloskey and his wife, Patricia, were indicted for infamously waving their guns at Black Lives Matter protestors who marched by their home last June.
Now pro-Trump Mr McCloskey has filed paperwork with the Federal Election Commission and launched a campaign website to raise money to compete for the state’s open senate seat in 2022.
He formally announced his campaign on Tucker Carlson’s Fox News show on Tuesday evening.
“I’ve always been a Republican, but I’ve never been a politician,” he told Carlson.
“God came knocking on my door last summer disguised as an angry mob, and it really did wake me up.”
And he added: “They (voters) don’t want any more posers and egotists and career politicians going to DC.”
“Mark is a Conservative outsider who will bring backbone and guts to the US Senate to continue fighting for President Trump’s agenda,” his website states.
Mr McCloskey and his wife, who were invited to speak at the Republican National Convention last year, are due to stand trial in November over the gun incident.
They were indicted in October by a St. Louis grand jury on felony charges of unlawful use of a weapon and tampering with evidence.
He will join the Republican field competing to replace retiring Senator Roy Blunt, for a seat that the GOP cannot afford to lose.
Democrats currently control the Senate, which is tied 50-50, as vice president Kamala Harris breaks any tied vote.
Missouri’s former governor Eric Greitens, who resigned in 2018 amid allegations he had an affair with his hairdresser and blackmailed and sexually assaulted her, has also announced he is running for the Republican nomination.
Former state Senator Scott Sifton and lawyer Lucas Kunce are among the Democrats who will contest the seat.
But whoever wins the Republican nomination will be heavily favoured to win the senate seat in the increasingly conservative state.
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies