The actress is set to play Susan Rodriguez-Jones, a new anchor at the New York news station where Fox's character, Mike, is returning to work after taking a five-year hiatus to battle Parkinson's disease.
The one-hour sitcom is loosely based on Fox's life as a man who has retired to spend time with his family as he battles disease.
"The Michael J. Fox Show" marks Fox's first regular return to the small screen since he retired after leaving "Spin City."
Heche's character is described as a "sharp, savvy and tough-as-nails" anchor who is Fox's character's rival.
The sitcom is set to debut Sept. 26 on NBC.