Grand Rapids Public Schools spokesman John Helmholdt said the janitor was fired Monday after a bystander reported the offer.
The janitor acknowledged her role, which occurred during lunch at Campus Elementary School. Helmholdt said that it's "absolutely unacceptable in any way, shape or form for an employee to behave in this manner."
An investigation is ongoing. Helmholdt said the remarks from the student involved included a "curse word and unflattering comments."
The janitor started working at Campus this year.