Gov. Rod R. Blagojevich of Illinois was arrested by federal authorities on Tuesday morning and charged with corruption, including an allegation that he conspired to profit from his authority to appoint President-elect Barack Obama’s successor in the United States Senate, prosecutors said.

As Mr. Blagojevich, a Democrat, mulled the Senate appointment, prosecutors say, he discussed gaining “a substantial salary” at a nonprofit foundation or organization connected to labor unions, placing his wife on corporate boards where she might earn as much as $150,000 a year and trying to gain promises of campaign money, or even a cabinet post or ambassadorship, for himself.

A 76-page affidavit from the United States Attorney’s office in the Northern District of Illinois says Mr. Blagojevich (pronounced bluh-GOY-uh-vich) was heard on wiretaps over the last month planning to “sell or trade Illinois’ United States Senate seat vacated by Pres-elect Barack Obama for financial and personal benefits for himself and his wife.”

The charges are part of a five-year investigation into public corruption and allegations of “pay to play” deals in the clubby world of Illinois politics. Federal authorities said Mr. Blagojevich’s chief of staff, John Harris, was also indicted on Tuesday. Both men are expected to appear in federal court for the first time later Tuesday.

Mr. Blagojevich, a Democrat in his second term who came into office in 2002, portrayed himself as a reformer after the one-term of the former governor, George Ryan, who was convicted of racketeering and fraud in 2006.

For more than a year, members of Mr. Blagojevich’s administration have been under investigation. But few here have imagined that the decision on replacing Mr. Obama might have resulted in criminal charges.

In addition to the charges related to Mr. Obama’s Senate seat, Mr. Blagojevich is accused of crimes related to past behavior. As part of the charges, he is accused, prosecutors say, of working to gain benefits for himself, his family and his campaign fund in exchange for appointments to state boards and commissions.

Under Illinois law, Mr. Blagojevich has sole authority to fill the seat being vacated by Mr. Obama, who was elected to the Senate in 2004.

According to the indictment, while talking on the telephone about the Senate seat replacement with his chief of staff and an adviser, Mr. Blagojevich said he needed to consider his family and their financial struggles. “I want to make money,” he said, according to prosecutors. He then added, they allege, that he wanted to make $250,000 to $300,000 a year.

In a release, Patrick Fitzgerald, the prosecutor, said Mr. Blagojevich “put a for sale sign on the naming of a United States Senator.”

Mr. Blagojevich even contemplated stepping into the Senate himself, prosecutors said.

“I’m going to keep this Senate option for me a real possibility, you know, and therefore I can drive a hard bargain,” Mr. Blagojevich said in a recorded conversation with an adviser, according to the affidavit. “You hear what I’m saying. And if I don’t get what I want and I’m not satisfied with it, then I’ll just take the Senate seat myself.”

According to the affidavit from prosecutors, Mr. Blagojevich told an adviser last week that he might “get some (money) upfront, maybe” from one of the candidates hoping to replace Mr. Obama. That person was identified only as “Candidate 5.”

In an earlier recorded conversation, prosecutors say, Mr. Blagojevich said he was approached by an associate of “Candidate 5” with an offer of $500,000 in exchange for the Senate seat.

The authorities also say Mr. Blagojevich threatened to withhold state assistance from the Tribune Company, the publisher of the Chicago Tribune and Los Angeles Times, which filed for bankruptcy on Monday. According to the authorities, Mr. Blagojevich wanted members of the Tribune’s editorial board, who had criticized him, to be fired before he extended any state assistance.

An official at the governor’s office had no immediate comment on Tuesday. A telephone message left at Mr. Obama’s transition office was not immediately returned.

Jack Healy contributed from New York.

WASHINGTON — Federal authorities on Wednesday identified Democratic Representative Jesse Jackson Jr. of Illinois as the potential United States Senate candidate who was portrayed in court papers made public Tuesday as being the most deeply enmeshed in the alleged scheme by Gov. Rod Blagojevich to benefit from his appointment of a new senator to the seat vacated by President-elect Barack Obama.

A lawyer for Mr. Jackson acknowledged that Mr. Jackson was the person identified as "Candidate 5" in the criminal complaint, but said that Mr. Jackson denied any wrongdoing and was not aware of anyone cutting deals on his behalf.

“Congressman Jackson has never authorized anyone to seek the governor’s support in return of money, fundraising, or other things of value,” the lawyer, James D. Montgomery Sr., said at a news conference in Chicago. "Secondly, the congressman is not aware of any alleged associate having made such a proposal.”

A short time later, Mr. Jackson appeared at a news conference here in which he angrily denounced Mr. Blagojevich, called for the governor’s resignation and asserted that he had done nothing wrong.

“I never sent a message or an emissary to the governor to make offers plead my case or propose a deal about a United States Senate seat, period,” Mr. Jackson said. “I thought mistakenly that the governor was evaluating me and other Senate hopefuls based on our credentials and qualifications.”

“I did not know the process had been corrupted,” he added.

Mr. Jackson said that he would meet with federal authorities and cooperate “fully and completely” with the investigation. He did not take questions to address his role as the anonymous Candidate 5 identified in the affidavit against Mr. Blagojevich.

Mr. Jackson said in an earlier interview with ABC News that he did not know whether he was Candidate 5 but added that the prosecutors in Chicago told him earlier this week that he was not a target of the criminal inquiry. Mr. Jackson and his representatives campaigned for the appointment publicly and visibly throughout November, trying to make the case that he was the favored candidate. An official in Mr. Jackson’s office, Kenneth Edmonds, provided the New York Times with a poll that commissioned before Election Day showing Mr. Jackson to be the most popular choice among Illinois residents.

In the news conference, Mr. Jackson said he met with Mr. Blagojevich for 90 minutes on Monday to discuss the job after not having spoken with him for more than four years. Mr. Jackson, the son of the civil rights leader, said he never authorized anyone to offer anything in return for the appointment.

Earlier in the day, Mr. Jackson said in comments broadcast by ABC News: “It is impossible for someone on my behalf to have a conversation that would suggest any type of quid pro quo or any payments or offers. An impossibility to an absolute certainty.”

Federal prosecutors in Chicago would not discuss the identity of Candidate 5 and would not comment on whether Mr. Jackson would be interviewed in the case.

The identity of Candidate 5 has been a mystery since the filing of a legal complaint on Tuesday accusing Mr. Blagojevich and an aide of engaging in corruption and conspiracy, stemming in part from an alleged effort by the Governor to sell off Mr. Obama’s seat in return for campaign contributions and lucrative jobs for Mr. Blagojevich and his family.

Of the six candidates for the senate seat who are identified by number in the complaint, but not named, only Candidate 5 is said to have engaged in possible wrongdoing by engaging in discussions through an emissary about a possible quid pro quo with Mr. Blagovich’s camp. The emissary was also not identified by name.

According to the compliant, Mr. Blagojevich threatened to appoint Candidate 5 to the vacant post, rather than another candidate he thought Mr. Obama would prefer, if Mr. Obama would not help place Mr. Blagojevich’s wife “on paid corporate boards right now.”

The complaint also said that in a wiretapped conversation on Oct. 31, Mr. Blagojevich told an associate about an approach by the emissary from Candidate 5: “We were approached ‘pay to play.’ That you know, he’d raise me 500 grand. An emissary came. Then the other guy would raise a million, if I made him [Senate Candidate 5] a senator.”

Susan Saulny contributed reporting from Chicago.