Police spokesman Athony Guglielmi tweeted Johnson was released from Rush Medical Center Monday afternoon and was on his way to his office to meet with command staff.
"Special thanks to the amazing doctors and nurses for their care and hospitality and thanks to everyone for all the well wishes & support," Guglielmi tweeted.
Friday, Guglielmi tweeted that Johnson was at his annual stress test at Rush when doctors found a small blood clot in his lung. He was kept in the hospital for observation over the weekend as the clot was treated by medication.