The former Chicago congressman son of civil rights leader the Rev Jesse Jackson has been charged with spending $750,000 (£483,000) in political campaign funds on personal expenses.
His wife has been charged with filing false income tax forms, in a spectacular fall from political prominence for the couple.
US government prosecutors filed a charge of conspiracy against Jesse Jackson Jr, and charged Sandra Jackson with one count of filing false joint federal income tax returns from 2006 to 2011. Both agreed to plead guilty in plea deals.
Democrat Jackson, 47, entered Congress in 1995 and resigned last November. His wife, known as Sandi, resigned as a Chicago city official last month.
Both face maximum penalties of several years in prison and Jackson also faces hundreds of thousands of dollars in fines and forfeitures. But the government did not immediately release the text of its plea agreements - such agreements almost invariably call for prosecutors to recommend sentences below the maximum.
"I offer no excuses for my conduct, and I fully accept my responsibility for the improper decisions and mistakes I have made," the ex-congressman said in a statement.
Jackson has been admitted to hospital twice since last June for bipolar disorder and other issues, and stayed out of the public eye for months, even during the November presidential election.
Several messages left with Jackson's father were not returned. The elder Jackson has often declined to comment about his son's health and legal problems over the past few months.
Jesse Jackson Jr's spending included $43,350 on a Rolex watch and $9,587.64 on children's furniture, according to court papers.
The filing said "defendant Jesse L Jackson Jr, willingly and knowingly, used approximately $750,000 from the campaign's accounts for personal expenses" that benefited him and his co-conspirator, who was not named in the one-count criminal information filed in the case.
The filing of a criminal information means a defendant has waived the right to have a grand jury consider the case; it is used by federal prosecutors when they have reached a deal for a guilty plea.
The prosecutors' court filing said that upon conviction, Jackson must forfeit $750,000 dollars, plus tens of thousands of dollars' worth of memorabilia items and furs.
The memorabilia includes a football signed by US presidents; a Michael Jackson and Eddie Van Halen guitar; a Michael Jackson fedora; and memorabilia of Martin Luther King, Malcolm X, Jimi Hendrix and Bruce Lee - all from a company called Antiquities of Nevada.
The conspiracy charge carries a maximum statutory penalty of up to five years in prison, a fine of up to $250,000, and other penalties.
Tom Kirsch, a lawyer for Jackson's wife, says she had signed a plea deal with federal prosecutors and would plead guilty to one tax count.
The charge against Sandi Jackson carries a maximum of three years in prison, but Mr Kirsch said the agreement "does not contemplate a sentence of that length".