Mich. Comp. Laws § 38.414
The classified service shall comprise all employees of the probate court, including the reporters employed thereby, deputy sheriffs, assistant prosecuting attorneys excepting the chief assistant prosecuting attorney, the chief trial attorney and the chiefs of the appellate division, civil division and criminal division and all positions not specifically included by this act in the unclassified service. All appointive officers and employees of the county or any subdivision thereof at the time this act shall take effect, and who shall have been such for more than 2 years prior thereto, whose positions this act includes in the classified civil service, shall hold their positions without examination until discharged, reduced, promoted or transferred, in accordance with the provisions of this act relating to civil service. All appointive officers and employees of the county or any subdivision thereof included in the classified civil service by this act who shall have been so employed for more than 1 year and less than 2 years prior to the time this act shall take effect shall be required to take qualifying examinations and all such appointive officers and employees who shall have been so employed for less than 1 year prior to the effective date of this act shall be required to take competitive examinations. Whenever the positions of any appointive officers or employees of the county shall be placed in the classified civil service of the county by amendment of this act subsequent to the time this act originally became effective in such county, such officers or employees shall hold their positions without examination until discharged, reduced, promoted or transferred in accordance with the provisions of this act, if they had been so employed for more than 2 years prior to the time their positions were so placed in the classified civil service, and such officers or employees shall be required to take qualifying examinations if they had been so employed for less than 2 years prior to the time their positions were so placed in the classified civil service. All employees now authorized by law to be employed in any county office or department for seasonal or temporary employment, who shall have been in such employment of the county for 2 successive seasons immediately prior to the time this act shall take effect, shall be included in the classified civil service and be eligible for appointment to such seasonal or temporary occupation without examination.
MCL 38.414