Craig Marquado said that Gallagher will remain hospitalized for at least one more night and that the comedian's two performances scheduled for Friday night in Illinois have been postponed.
The 64-year-old performer collapsed in the middle of a show at the Whiskey Bone's Roadhouse in Rochester, Minn. on Thursday night.
A witness, Chris Blade, told the Rochester Post-Bulletin that Gallagher had complained of pain in his left arm and shortness of breath earlier in the evening. Blade said Gallagher was responsive when emergency crews were taking him out of the club.
Gallagher, whose real name is Leo Anthony Gallagher, is best known for smashing watermelons with a sledgehammer.
The Associated Press contributed to this report.