A labor organizer at the center of much of the corruption within Ironworkers Local 401 was sentenced to eight years in prison Thursday for his leadership in the group's long-standing efforts to maintain a grip on city construction jobs through violence and intimidation.

Edward Sweeney, the union's one-time business agent overseeing work in Philadelphia, apologized to U.S. District Judge Michael Baylson for the role he played in recruiting members to commit dozens of acts of extortion and sabotage, including a 2012 arson at the construction site of a planned Quaker meetinghouse in Chestnut Hill.

"I truly am sorry for my actions and my inactions for the incidents that occurred," he told the judge.

Baylson granted a government request to set aside mandatory minimum sentences for many of Sweeney's crimes. They could have sent him to prison for 115 years.

However, the judge rejected suggestions from prosecutors that Sweeney should serve as little as six years because of his guilty plea and testimony in the trial of longtime union head Joseph Dougherty, who was convicted this year.

"He was the top lieutenant to Mr. Dougherty," Baylson said. "Mr. Dougherty relied on Mr. Sweeney for hands-on criminal conduct. Mr. Sweeney was ready, willing, and able when it came to committing crimes."

Assistant U.S. Attorney Robert J. Livermore described Sweeney's case as one "of extremes."

On one hand, he said, Sweeney either oversaw or participated in some of the city's most notable acts of union sabotage in recent years.

The meetinghouse torching? He gave the OK. The extortion of a company building a Center City communications tower? He strong-armed builders into hiring his colleagues for no-work jobs. An attempted arson at a construction site in Malvern? Sweeney provided the torch.

On the other, his lawyer Carmen Nasuti said, Sweeney's decision to plead guilty and testify against Dougherty provided prosecutors with some of its strongest evidence linking the union head to the crimes of its members.

"Dougherty, who had been running this union forever, laid down the law and wanted these things done," Nasuti said. "If Sweeney wasn't getting the job done, there were numerous other business agents who would do it for Mr. Dougherty."

In addition to his prison term, Sweeney was ordered to pay $217,612 in restitution.

Prosecutors have alleged that violence was so ingrained in the union's structure, that willingness to participate in arson, vandalism, and beatings on picket lines - called "nightwork" - often decided who received plum jobs or moved up the ranks in the union hierarchy.

In all, 12 Ironworkers were convicted in the case. Three - including Dougherty - remain to be sentenced.