A Proud Boy from Florida who went on the lam after being convicted of using pepper spray on police officers during the attack on the Capitol on Jan. 6, 2021, was sentenced on Thursday to 10 years in prison.

The Proud Boy, Christopher Worrell, was found guilty at a bench trial in Federal District Court in Washington in May on charges of assault, civil disorder and the obstruction of an official proceeding for his role in the Capitol attack. Prosecutors said that Mr. Worrell, 52, arrived in Washington on Jan. 6 “ready for battle” and wearing body armor, and with other members of the far-right organization “played a pivotal role in collapsing the police line on the west front, leading to the first breach of the Capitol building.”

The Proud Boys, who have long been some of former President Donald J. Trump’s most vocal and violent supporters, were at the forefront of the violence on Jan. 6, pushing through barricades and encouraging others in the mob to attack the police and storm the Capitol, where lawmakers had gathered to certify the results of the 2020 presidential election.

Dozens of members of the group were investigated by the F.B.I., and many either pleaded guilty or were brought to trial in Washington. Four of them, including the Proud Boys’ former chairman, Enrique Tarrio, were convicted last spring on charges of seditious conspiracy.

Prosecutors said that Mr. Worrell, a member of the “Hurricane Coast” chapter of the Proud Boys, started to encourage a violent response to Mr. Trump’s loss in the election well before Jan. 6. On the encrypted app Telegram, he wrote his fellow Proud Boys messages saying things like “Resist Like It’s 1776” and “Remember George Washington attacked and saved the Union on Christmas Eve.”

Mr. Worrell arrived in Washington with a half-dozen other Proud Boys, prosecutors said, and on the morning of Jan. 6 joined a larger contingent of the group at the Washington Monument wearing body armor, ear protectors and a GoPro-style video camera. He also carried two canisters of Sabre Red Maximum Strength Pepper Gel, prosecutors said.

Not long after the Capitol’s perimeter was breached, Mr. Worrell and other Proud Boys marched in what prosecutors called “a coordinated stack formation” onto the Capitol grounds. Videos from the day captured Mr. Worrell shouting, “Trump is coming to the Capitol.”

Ultimately, Mr. Worrell used his pepper spray on a group of police officers, allowing a portion of the mob to surge up stairs outside the Capitol and become some of the first rioters to break into the building.

When Mr. Worrell went on trial in Washington in April, he showed no remorse for his actions, telling “falsehood after incredible falsehood in an effort to deflect responsibility and cast himself as a hero intervening to protect the police” against members of the leftist movement antifa, prosecutors said.

In written notes about his verdict convicting Mr. Worrell, Judge Royce C. Lamberth called Mr. Worrell’s contention that he had used the pepper spray on antifa members “preposterous,” and said that the evidence prosecutors introduced demonstrated that Mr. Worrell had been at the Capitol that day “for the purpose of ensuring that the Electoral College certification of President Biden failed.”

In August, just four days before his initial date for sentencing, Mr. Worrell cut off his G.P.S. ankle monitor in the parking lot of a Walmart and went on the run. He was ultimately caught six weeks later at his home in Naples, Fla., and returned to Washington for a new sentencing hearing.