Tennessee Code Title 6. Cities and Towns § 6-4-301

(2) In the absence or disability of the city judge, the mayor may designate a qualified person to serve as city judge or, to the extent the general sessions court judge agrees to serve as city judge, may designate the general sessions court judge of the county or counties in which the municipality lies to be acting city judge until one can be appointed at the next regularly scheduled meeting of the board, or as otherwise provided by ordinance.

(c)(1) The board may require, by ordinance, that the city judge meet the constitutional qualifications and be elected in the same manner as a judge of an inferior court. Constitutional provisions applicable to judges of inferior courts shall apply to the elected city judge.

(2) If an elected city judge is temporarily unable to preside over the city court for any reason, then, to the extent a general sessions court judge agrees to serve temporarily as city judge, the judge shall appoint a general sessions judge of the county or counties within which the municipality lies to sit in the judge's place. If no general sessions judge is available, then the city judge shall appoint an attorney, meeting the same qualifications as a general sessions judge, to sit temporarily.