CHICAGO - Nearly three months after taking a medical leave from Congress, Rep. Jesse Jackson Jr., D-Ill., returned home to his family in Washington, D.C. today, according to one of his aides.

Jackson has been undergoing treatment for bipolar disorder at the Mayo Clinic this summer.

"He's at their house in Washington," Rick Bryant, Jackson's chief of staff, told ABC News today. "All I've got is he's at home with his family."

In June Jackson, the son of civil rights leader Jesse Jackson, abruptly left Congress. His office initially said the congressman, who represents a district that includes a large portion of Chicago's South Side and southeast suburbs, was taking a medical leave of absence to seek treatment for exhaustion. Two weeks later his office said his condition was "more serious than we thought." After spending some time at a facility in Arizona, Jackson was transferred to the Mayo Clinic in Rochester, Minn. Last month the clinic released a statement that the congressman was being treated for bipolar disorder and was "responding well to the treatment and regaining his strength."

According to a source close to the congressman who spoke to him today, Jackson "sounded good." Congress ends its summer recess next week.

Jackson's leave from Congress came at a difficult time for him. He is currently involved in a reelection race and he is the target of a probe by the House Ethics Committee into possible wrongdoing in how President Barack Obama's Senate seat - now held by Sen. Mark Kirk - was filled. Only days before Jackson left Congress on medical leave, one of his former fundraisers, Raghuveer Nayak, was arrested by the FBI on charges of paying hundreds of thousands of dollars in bribes to doctors.

Jackson has faced turmoil at home, too. Last year his wife Sandi revealed that Jackson had engaged in an extramarital affair.