Dolan was arrested in May and is among 20 members and associates of the Oath Keepers accused of conspiring to block the certification of President Joe Biden's victory in last year's election.
He pleaded guilty to one count of conspiracy and one count of obstruction of an official proceeding. The judge said federal sentencing guidelines call for a term of more than five years to six-and-a-half years behind bars. An email seeking comment was sent to Dolan's attorney.
Members of the Oath Keepers and the Proud Boys, make up a fraction of the more than 600 people charged with federal crimes in the riot. But they face some of the most serious charges, including those involving accusations they plotted to thwart the certification of the Electoral College vote.
Authorities say that days before the riot, Dolan and other extremists joined an invitation only encrypted Signal message group called "OK FL DC OP Jan 6."
On Jan. 6, he and the other defendant, who were in the crowd on the east side Capitol steps, joined up with other Oath Keepers dressed in tactical vests and helmets who were marching toward the door in a military-style stack formation. The group forcibly entered the building, authorities say in court documents.
Prosecutors say after the riot, Dolan and other Oath Keepers gathered outside the building with the group's founder, Stewart Rhodes. Rhodes has not been charged in the attack but has repeatedly come up as “PERSON ONE” in court documents, suggesting he's a central focus for investigators.
The three other Oath Keepers who pleaded guilty to conspiracy charges are also cooperating with investigators and have yet to be sentenced.
FBI agents last week seized the phone of the Oath Keepers' general counsel, Kellye SoRelle, according to SoRelle. A search warrant — which SoRelle provided The Associated Press a photo of in a Signal message — says it is related to an investigation into seditious conspiracy, among other crimes.
SoRelle said she had no knowledge of or involvement in the Capitol breach, calling the seizure of her phone “unethical” and the investigation “a witch hunt."
Authorities have also seized Rhodes' phone, she said. Rhodes has insisted that the members went rogue and there was never a plan to enter the Capitol.
No one arrested in the Jan. 6 riot has been charged with sedition, even though then-District of Columbia U.S. Attorney Michael Sherwin floated it as a possibility in the weeks after the attack.
Only one person who has admitted to a felony charge so far has received their punishment. Paul Hodgkins — a crane operator from Florida who pleaded guilty to obstruction of an official proceeding — has been ordered to report to prison on Monday to begin serving his eight month term.
Hodgkins sought to delay the start of his prison sentence for several months as he tries to challenge his case after hiring a new attorney, but a judge on Wednesday denied his bid to remain free.