In the papers, signed within the past several days, Jackson admitted using campaign contributions for personal items such as a $40,000 Rolex watch, furniture for his Washington home and travel expenses for a friend.
Those knowledgeable about the investigation said they think any remaining issues concern Jackson's wife, former Chicago Council Member Sandi Jackson, and whether she would be charged, WMAQ said.
Under the terms of the deal, Jackson pleaded guilty to one count of misusing campaign funds and a judge is to decide whether to sentence him to probation or up to five years in prison.
The plea agreement also requires Jackson to repay the government hundreds of thousands of dollars in campaign funds he converted to his personal use.
The only thing Jackson's father, the Rev. Jesse Jackson Sr., said about his son's case Thursday was that "it's painful," WBBM-TV, Chicago, reported.
The younger Jackson resigned from Congress before Thanksgiving amid a federal investigation into misuse of campaign funds and mental health issues. The former congressman had been diagnosed with bipolar disorder and was on medical leave from Congress since June.