CHICAGO -- U.S. Rep. Jesse Jackson Jr. resigned from Congress effective Wednesday, citing the need to spend time "restoring my health."
Jackson, who announced his resignation in a letter to House Speaker John Boehner, has been is the subject of several investigations and was recently treated at the Mayo Clinic for what was described as "several serious health issues."
Voters in his South Side Chicago district re-elected Jackson, 47, for a 10th two-year term this month, despite his legal and health troubles.
"The constituents of the Second District deserve a full-time legislator in Washington, something I cannot be for the foreseeable future," he wrote to Boehner. "My health issues and treatment regimen has been incompatible with service in the House of Representatives. Therefore, it is with great regret that I hereby resign as a member of the United States House of Representatives, effective today, in order to focus on restoring my health."
Jackson, the son of civil rights leader the Rev. Jesse Jackson, is the subject of investigations by the FBI and the House Ethics Committee involving possible financial improprieties.
His House colleagues are looking into allegations that he or one of his associates offered to raise money for then-Illinois Gov. Rod Blagojevich in exchange for Jackson being appointed to the Senate seat vacated by Barack Obama in 2008.
"During my journey I have made my share of mistakes," Jackson said in his resignation letter. "I am aware of the ongoing federal investigation into my activities and I am doing my best to address the situation responsibly, cooperate with my investigators, and accept responsibility for my mistakes, for they are my mistakes and mine alone. None of us is immune from our share of shortcomings or human frailties and I pray that I will be remembered for what I did right."
Illinois Gov. Pat Quinn has five days after the resignation is confirmed to set a date for a special election to fill the seat vacated by Jackson.
"This election will be carried out in a manner that is fair to the electorate and as economical as possible for taxpayers," Gov. Quinn said Wednesday.
U.S. Rep. Bobby Rush, who represents another Chicago district, suggested Wednesday that Jackson waited until after the election to step aside to make sure voters could chose his successor. Otherwise, a few people in the Chicago power structure would have been able to "choose one of their lackeys to be the congressman."
Rush warned there could be confusion, though, if too many people jumped into the race to replace Jackson. "My fear is that there are going to be so many wannabees who are guided by blind ambition that we might find a tea party representative from the second congressional district, which would be a travesty in itself," Rush said
Jackson sounded "sounded very, very sorrowful," in a phone call Wednesday morning, Rush said. "He sounded in so much pain."
"As he works to address his health, our thoughts and prayers are with him, his wife Sandi, his children as well as his parents," House Minority Leader Nancy Pelosi said. "We are grateful to him and his family for their long-standing record of public service to our country."
Jackson has been out of the public eye and absent from Capitol Hill for much of the past year, including while he was being treated at the Mayo Clinic as recently as last month.
He made no campaign appearances, relying instead on a recorded automated call to constituents in October in which Jackson said, "the good news is my health is improving, but my doctors tell me the road to recovery is a long one."
"Like many human beings, a series of events came together in my life at the same time and they've been difficult to sort through," he said in the call, which his office provided to CNN. "I am human, I am doing my best, and I am trying to sort through them all."
In early July, the congressman's office announced he was "receiving intensive medical treatment at a residential treatment facility for a mood disorder." A few weeks later, his office said he was undergoing an "extensive inpatient evaluation for depression and gastrointestinal issues" at the Mayo Clinic.
Jackson grew up in his father's shadow, placing him on history's stage as the Rev. Jesse Jackson Senior led civil rights campaigns, including Operation PUSH and the Rainbow Coalition.