"I would never knowingly break any game laws," Nugent told the court. "I'm afraid I was blindsided by this, and I sincerely apologize to everyone for this."
With his plea, the singer and avid hunter followed through with a signed agreement he made with federal prosecutors earlier this month.
Magistrate Judge Michael Thompson accepted the deal at a U.S. District Court hearing in Ketchikan. Nugent and his attorney participated by telephone.
According to the document, Nugent illegally shot and killed the bear in May 2009 in southeast Alaska after wounding another bear in a bow hunt. The bow incident counted toward a state seasonal limit of one bear. Nugent and his lawyer, Wayne Anthony Ross, said neither of them knew about that law.
The judge said he wasn't aware of the "sort of one-strike policy" either.
The plea agreement says Nugent knowingly possessed and transported the bear in misdemeanor violation of federal law.
Ross said after the hearing that he was unaware of any state charges pending. A database search found no state charges against Nugent.
"It seems to me that would be double dipping," Ross said.
The hunt was filmed for Nugent's Outdoor Channel television show "Spirit of the Wild," according to the plea deal.
Under the agreement, Nugent must pay a $10,000 fine and serve two years of probation, including a special condition that he not hunt or fish in Alaska or on U.S. Forest Service properties for a year. Nugent used a number of bear-baiting sites on Forest Service land during the Alaska hunt, the document said.
He also must create a public service announcement that will be broadcast on his show every second week for a year after approval by a representative of the U.S. Attorney's Office.
Nugent told the court he wanted to make numerous PSAs to keep the interest level up, "so it's not just the same statement." Thompson said that would be fine, as long as the PSAs were approved before airing.
The musician famed for his 1977 hit "Cat Scratch Fever" also must pay the state $600 for the bear that was taken illegally.
Nugent briefly drew the attention of the Secret Service last week after he rallied support for Republican presidential candidate Mitt Romney and said of the Obama administration: "We need to ride into that battlefield and chop their heads off in November."
His comments were made during a National Rifle Association meeting in St. Louis.
As a hunter, Nugent has run afoul of the law before.
In August 2010, California revoked Nugent's deer hunting license after he pleaded no contest to misdemeanor charges of deer-baiting and not having a properly signed tag.
Nugent's loss of that deer hunting license through June 2012 allows 34 other states to revoke the same privilege under the Interstate Wildlife Violator Compact. Each state, however, can interpret and enforce the agreement differently.