"My recovery is coming along well," Johnson told reporters, noting that his doctors have not yet cleared him to return to work. "My doctors are actually kind of amazed at how quickly I bounced back."
Johnson said he hoped to return to work within the next couple of weeks.
Johnson returned to Chicago Police headquarters for the first time since the Aug. 30 surgery to address an audit conducted by Chicago Inspector General Joseph Ferguson that found "wide scale waste and a culture of abuse" in how the department paid officers overtime.
Johnson's 25-year-old son, Daniel, who donated part of his kidney to his father, is "bouncing around" as if he had not undergone the surgery, the superintendent said.
First Deputy Supt. Kevin Navarro has run the department in Johnson's absence, which is expected to be no more than a few weeks, officials said.
Johnson told reporters in January that he was diagnosed with a kidney disease 32 years ago when he applied to be a Chicago police officer and was required to take a blood test. He said he has managed it since then without medicine.
Before his surgery, Johnson was one of 123,000 Americans on the organ transplant list. However, only 7,000 people receive a transplant each year; 12 people die every day waiting for a kidney.
Half of the 4,700 people awaiting a transplant in Illinois are minorities, according to the Office of Illinois Secretary of State Jesse White.