Douglas Wright of Indianapolis was sentenced to 138 months in prison. He apologized in court to his family and the community, saying he was an addict and needed help for substance abuse, not just prison.
Two other men — 20-year-old Brandon Baxter of Lakewood and 20-year-old Connor Stevens of Berea — were to learn their sentences later Tuesday.
Judge David Dowd had ruled last week that the men should be sentenced as terrorists, making them subject to harsher prison terms.
A fourth defendant will be sentenced Wednesday and a fifth is undergoing a psychiatric exam.
Stevens, Baxter and Wright pleaded guilty to conspiring to use a weapon of mass destruction, knowingly attempting to use a weapon of mass destruction and attempting to damage property with explosives. There was no plea deal that would have reduced their sentences.
Last week Dowd backed a government request to consider stricter sentences based on a "terrorist enhancement" for the trio. The ruling that the three were trying to intimidate the government expanded possible sentences from five or six years to 15 to 30 years or more.
The men were arrested by the FBI and had targeted a bridge over the Cuyahoga Valley National Park between Cleveland and Akron. The FBI has said the public was never in danger and the device was a dud provided by an informant.
The suspects were described by the government as self-proclaimed anarchists who acted out of anger against corporate America and the government.
The defense called the case entrapment, with the informant guiding the way, and said the plot was more an act of vandalism than anti-government terrorism. They asked for sentences in the range of five years.
The government said the plot "was meant to convey a message to the civilian population, the corporate world, the financial system, and all levels of government."