In a letter, Mayor Jason House said there's been division in the community.
Some Dolton Firefighters have said Curtis doesn't have the certification needed to lead the department, and they say he's putting them at risk.
Mayor House says this move is meant to help the community heal and move forward together.
Firefighters in Dolton took to the streets, raising concerns about safety in the south suburbs on Monday.
READ MORE | Dolton firefighters hold protest over safety issues, questions surrounding fire chief's eligibility
The exact reason for Curtis' decision to take a leave from the department was not yet known.
No further information was immediately available.