Miss. Code Ann. § 21-8-25

The council of any municipality adopting the mayor-council form of government may, within its discretion, adopt an ordinance providing that the mayor shall appoint, with the advice and consent of the council, a chief administrative officer to coordinate and direct the operations of the various departments and functions of municipal government; such chief administrative officer shall serve at the pleasure of the mayor and shall possess such qualifications and experience as shall be set out in the aforesaid ordinance. The said chief administrative officer shall be answerable solely to the mayor in the performance of his functions and shall be subject to dismissal at the pleasure of the mayor and shall be excluded from the coverage of any ordinance or general law providing for a civil service system in the municipality.