The comedian, who first became famous in the 1970s for his props-based physical comedy shows, was rushed to hospital on Wednesday (March 14) after experiencing chest pains prior to a live show in Texas. It was later confirmed that he had suffered a "mild to serious" heart attack.
Gallagher's manager told E! Online that he is now breathing on his own and moving around.
Confirming that her client has also begun telling jokes again, Christina Scherrer added: "We're not sure how long the doctors will want him to stay yet... so far so good, can't wait to have him back!"
Gallagher - born Leo Anthony Gallagher - was admitted to hospital 12 months ago after he developed chest pains on stage during a performance in Minnesota.
He was discharged three days later, following a mild heart attack.