Ok, cities operate on a charter which states what can and cannot be done within the Corporate form of government. Counties, unless they have adopted "home rule" like Knox County must follow state law. State law does not restrict County Employees from being on Commission or School Boards.
"Qualifications. There are no extraordinary qualifications to hold the office of countycommissioner. However. a person must comply with the general requirements for holding office in this state. All persons 18 years old and over, who are citizens of the United States and of Tennessee, and who meet certain residency requirements are [/b]qualified to hold office unless the person:
1. Has been convicted of offering or giving a bribe, of larceny, or of any otherm offense declared infamous by law, unless the person has been restored to citizenship as prescribed by law;
2. Has not paid a judgment for money received in an official capacity, which is due to the United States, Tennessee, or any county;
3. Has defaulted to the treasury at the time of election (in which case the election is void);
4. Is a soldier, seaman, marine, or airman in the regular United States Army, Navy or Air Force; or
5. Is a member of Congress or holds any office of profit or trust under anyforeign power, other state of the Union, or the United States. T.C.A.§ 8-18-101. County commissioners must reside within and be qualified voters of the district represented. T.C.A. § 5-5-102. County employees otherwise qualified to serve may hold office as a legislative body member, except that a director of schools who was not a
member of the county legislative body on June 18, 2005, is not qualified. T.C.A. § 5-5-102. However, no person elected or appointed as county mayor, sheriff, trustee, register, county clerk, assessor of property, or any other countywide office filled by popular vote or by the legislative body may be nominated for or elected to the legislative
body. T.C.A. § 5-5-102. If a legislative body member accepts the nomination as a candidate for the office of county mayor, sheriff, trustee, register, county clerk, superintendent of roads, superintendent of schools, circuit court clerk, assessor of
property, general sessions judge, or General Assembly member when the office is being filled by the legislative body, that member becomes disqualified to continue in office, and a vacancy in the county commission will automatically exist. T.C.A. §5-5-102.
From this link: page 5;
http://ctas-notes.ips.utk.edu/PUBLIC/web...ok2007.pdf
Now does State law does restict it for cities:
6-31-105. Eligibility for office of council member. —
Any qualified voter of the city is eligible for election to the office of council member; provided, that such voter has been a resident of the city for one (1) year next preceding the day of election; and provided further, that before taking office, the voter resigns any state, county, or other municipal office or position of employment that is filled by public election or that is remunerative, except as a notary public or member of the national guard.
[Acts 1957, ch. 238, § 3.05; T.C.A., § 6-3106.]
remunerative: for profit and this may be the clause or statment that got this school teacher.
County governments and city governments are two completely different animals under the law of the State of TN. County government is considered a subsidary of State government. City Government is an independent corporation with autonomy but for basic guidelines.