Twitter is permanently banning Alex Jones and his Infowars show for abusive behaviour.
The social media site said Jones will not be able to create new accounts on Twitter or take over any existing ones.
It said Jones posted a video on Wednesday in violation of the company's policy against "abusive behaviour".
The video in question shows Jones shouting at and berating CNN journalist Oliver Darcy for some 10 minutes during congressional hearings about social media.
Jones had about 900,000 followers on Twitter and Infowars had about 430,000.
Twitter had previously suspended Jones for a week but until now had resisted muzzling Jones further.
Other tech companies have limited Jones by suspending him for longer periods, as Facebook did, and by taking down his pages and radio stations.