The Onion said that the bid was secured with the backing of families of victims of the Sandy Hook Elementary School shooting, who won a $1.5bn (£1.18bn) defamation lawsuit against Jones for spreading false rumours about the massacre.
A judge in Texas ordered the auction in September, and various groups – both Jones’s allies and detractors – had suggested they would bid for the company.
Jones founded Infowars in 1999. He has vowed to continue broadcasting using a different platform.
In a rambling video message posted on Thursday morning, Jones called the takeover a “total attack on free speech”.
“I don’t know what’s going to happen but I’m going to be here until they come in and turn the lights off,” he said. “This is the tyranny of the New World Order, desperate to silence the American people, the mandate of Trump against all the lawfare – they don’t care.”
The Onion plans to rebuild the website and feature well-known internet humour writers and content creators.
“We are planning on making it a very funny, very stupid website,” said Ben Collins, a former NBC News journalist who is chief executive of The Onion’s parent company, in a statement.
The website also posted a jokey article, saying that Infowars “has shown an unswerving commitment to manufacturing anger and radicalizing the most vulnerable members of society”.
The article went on to say that the satirical publication “has outwitted the hapless owner of InfoWars” and “forced him to sell it at a steep bargain: less than one trillion dollars”.
A lawyer for families of eight of the Sandy Hook victims said the bid had their support.