Bertino appeared before US District Court Judge Tim Kelly to enter his guilty plea, which also included a count of unlawful possession of a firearm, the report said on Thursday.
Bertino was involved in key conversations and chats with other members of the Proud Boys, including the group's national chair Enrique Tarrio and other leaders, the report added.
In documents accompanying his plea, Bertino joined the Proud Boys in 2018 and admitted to attending the Washington rallies with the group after the 2020 US presidential election, according to the report.