McMichael has been receiving treatment for a MRSA infection and a UTI since being admitted to a hospital last Thursday.
The 66-year-old McMichael went public with an ALS diagnosis three years ago.
McMichael was admitted into intensive care on Thursday - a week after being voted into the Pro Football Hall of Fame - with a urinary tract infection. The family announced Saturday he had developed MRSA, a staph infection that can be difficult to treat because it is resistant to certain antibiotics, and was undergoing a blood transfusion.
READ MORE | Bears great Steve McMichael improving from staph infection, family hopes to have him home Tuesday
His wife, Misty, shared an update on Sunday, saying, "Steve is responding to the antibiotics and his condition is improving... He's one tough guy. He's Mongo, and his DNA is different."
The Associated Press contributed to this report.