CHICAGO (CBS) — Chicago Police Supt. Eddie Johnson successfully received a kidney transplant from his 25-year-old son at Rush University Medical Center, the hospital said Wednesday.

“Everything went smoothly and as expected for both donor and recipient,” an update issued Wednesday night said. “Superintendent Johnson is in fair condition: vital signs are stable, he is conscious and comfortable and indicators are favorable.”

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Johnson and his family arrived at Rush shortly after 6 a.m. The surgery began around noon, and was to take 3 to 4 hours for Johnson and his son, Daniel.

“I just really want to thank the citizens of Chicago. The support that my son and I have gotten is unexpected and overwhelming,” Johnson told media before the procedure. “It’s not really about Eddie Johnson. It’s about shining a spotlight on organ donation, period; but I’m proud of him, because it’s a decision that he made on his own, you know? And it’s humbling.”

Johnson has been suffering from a rare kidney disease for more than 30 years.

The city’s top cop revealed he suffers from a rare kidney disease earlier this year, after falling ill at a press conference in January.

His kidneys were functioning at 10 percent capacity. When his son learned about that, he offered to donate one of his kidneys to his dad. After the surgery, part of his son literally will be living within Johnson.

“Part of me is in him, so you know he’s just giving it back to me,” he said. “I just hope that I don’t get the urge to do things college kids do.”

All kidding aside, Johnson said he expects the indissoluble bond between father and son will only strengthen after their joint surgeries.

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“I think it will be even tighter, you know? I do. We always had love for each other, and him being my only son, you cherish your only son as a father, you really do. So he’s just made me proud,” he said.

Johnson’s surgeon, Dr. Edward Hollinger Jr., said the superintendent can expect to spend 3 to 5 days at the hospital after Wednesday’s surgery, and then 3 to 6 weeks recovering at home doing normal activities, but no heavy lifting.

Hollinger said, when he performs a kidney transplant, he does not remove the recipient’s old kidneys.

“Unless there’s an issue that causes us to remove them, which is pretty rare, we leave the recipient’s existing kidneys in place. So when someone gets a kidney transplant, almost always they’re walking out of the hospital with three kidneys,” he said.

Johnson dropped more than 45 pounds before the transplant, and doctors also told his son to lose weight before donating his kidney. The superintendent has said his doctors told him losing weight before the transplant will reduce the recovery time after surgery.

Since he found out he would need a new kidney, Johnson has been an active supporter of Gift of Hope Organ & Tissue Donor Network.

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Chicago Police First Deputy Supt. Kevin Navarro will lead the department while Johnson recovers.