The Dale Horvath actor will play a construction worker who gets caught up in a harrowing situation, and must turn to Taylor Kinney's Lieutenant Kelly Severide to get him through it, according to Entertainment Weekly.
Executive producer Dick Wolf has asserted that the new NBC show - which follows the lives of firefighters and paramedics in the Chicago Fire Department - has the potential to be iconic.
House's Jesse Spencer will star alongside Kinney in Chicago Fire as Lieutenant Matthew Casey.
DeMunn also recently rejoined forces with The Walking Dead's Frank Darabont for TNT pilot LA Noir.
Chicago Fire premieres on October 10 on NBC.
Watch a trailer for the show below: