Sgt. David Mueller served 23 years with the Joliet Police Department after serving four years of active duty in the 82nd Airborne Division of the Army. He has continued his military connection by serving in the National Guard.
The suit claims Mueller was placed on unpaid leave by the department, forcing him to leave the guard and return to work.
Mueller's attorney said his military service should be protected by state and federal laws which ensure employees who serve in the National Guard and Reserves will be paid and maintain vacation time and other benefits.
However, Joliet has failed to do that, they say.
"They knew the law, they just didn't want to follow it," said Mueller's attorney, Heidi Karl Sleper.
Mueller also alleges that, at one point, the police chief "yelled at and belittled" him, "stating that he was (expletive) over the department by leaving and trying to double dip on pay," according to the lawsuit.
Mueller was chosen for the Guard's counter drug task force serving in Joliet, he said.
However, Joliet placed him on unpaid leave of absence, forcing him to leave the task force early to return to work on the police department.
Joliet's city attorney declined to comment on the lawsuit, saying: "We are aware of the lawsuit and have engaged private legal counsel."
Mueller, who said he's close to retirement age with the police department, said he hopes to receive back-pay and have his benefits restored.