Dominic Pezzola was the latest to be jailed after leaders of the group were convicted of spearheading an attack aimed at preventing the peaceful transfer of power from Donald Trump to Joe Biden after the 2020 presidential election.

The 46-year-old took a police officer's riot shield and used it to smash a window, allowing rioters to make the first breach into the Capitol.

He later filmed a "celebratory video" with a cigar inside the building, prosecutors said.

Pezzola was a recent Proud Boys recruit, however, and a jury acquitted him of the most high-profile charge of seditious conspiracy.

"He was an enthusiastic foot soldier," prosecutor Erik Kenerson said.

US District Judge Timothy Kelly noted that Pezzola, of Rochester, New York, was a newcomer to the group who did not write the kind of increasingly violent online messages that his co-defendants did leading up to the attack.

However, he was in some ways a "tip of the spear" in allowing rioters to get into the Capitol, the judge added.

"The reality is you smashed that window in and let people begin to stream into the Capitol building and threaten the lives of our lawmakers," the judge told Pezzola.

"It's not something that I ever dreamed I would have seen in our country."

The defence had asked for five years for Pezzola, saying he got "caught up in the craziness" that day.

Pezzola told the judge that he wished he had never crossed into a restricted area on January 6 and he apologised to the officer whose shield he took.

"There is no place in my future for groups or politics whatsoever," he said.

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But later, as he left the courtroom, he raised a fist and said: "Trump won!"

Two co-defendants were sentenced on Thursday.

Joseph Biggs, an organiser from Ormond Beach, Florida, got 17 years, and Zachary Rehl, a leader of the Philadelphia chapter, got 15 years.

More than 1,100 people have been charged with Capitol riot-related federal crimes. Over 600 of them have been convicted and sentenced.