“I was the first major candidate in modern times to promote the term and policy of ‘America First,’” Duke said. “We cannot have free trade without fair trade.”
“I’m overjoyed to see Donald Trump and most Americans embrace most of the issues I’ve championed for years,” he said. ”I’ve always opposed these wars that lead our nation to disaster.”
Duke endorsed Trump's presidential run in February, and called on supporters to help the New York developer's White House campaign.
Trump was criticized by Democrats and Republicans for not doing enough to distance himself from the former KKK leader's support, as well as re-tweeting white supremacist imagery.
Duke has unsuccessfully sought a Senate seat before. He also ran for president unsuccessfully in 1992.
Under Louisiana’s "jungle" primary system, if no candidate wins a majority of votes in November, the top two candidates will face off in a December runoff election.
The National Republican Senate Committee Executive Director Ward Baker was quick to say the committee would not be supporting Duke.
Duke's leading opponents have also denounced his rhetoric and Senate campaign.