Any employee of the state of Tennessee, or political subdivision thereof, or a former employee of a political subdivision, and who was an employee in the service of the state of Tennessee, or political subdivision thereof, or who held the elective office of county court clerk or general sessions judge, or of the educational system of the state or any county, city, or special school district receiving funds from the state of Tennessee, or that has been a member or is now a member of the state retirement system who has been separated from state service and who either did or did not withdraw their contributions and later returned to the state service, shall be eligible to receive credit toward retirement and retirement benefits in said state retirement system for such period of employment service, both before and after the establishment of said state retirement system, upon the following conditions:
Any employee who has been a member or is now a member of the state retirement system who has been separated from state service and withdrew his contributions and later returned to the state service shall be allowed to claim his prior service and pay back into the retirement system the amount withdrawn, such payments to be made in accordance with the provisions of subdivision (B) of this section.
Any member of the general assembly who is or who becomes a member of the Tennessee state retirement system shall be permitted to claim as creditable service his years of legislative service prior to membership, provided he pays into the retirement system the amount determined under the provisions of subdivision (B) of this section, as if such legislative service were prior service. The limitations contained in this section concerning the time within which to apply for such credit or to pay in such contributions shall not apply to this paragraph. Any person who has retired under the provisions of the Tennessee state retirement system and who is or becomes a member of the general assembly may rejoin the system as a member and claim credit for any uncredited time served as a member of the general assembly by paying into the system the amount of money he would have paid into the system if he had been a member during the time for which credit is claimed. Upon such members' rejoining the system, no benefits shall be payable to him while he continues as an active member.
Any other provision to the contrary notwithstanding, any former employee of a political subdivision may be eligible for retirement benefits of this system if the political subdivision has elected to allow a class of employees to participate in this system and the former employee is within the class so participating, and the former employee and the local political subdivision in its sole discretion, make the prior service contribution provided in § 8-3604.
Any member of the Tennessee state retirement system shall be entitled to credit for time served as sheriff in any county in the state of Tennessee. Any person claiming credit for prior service under the provisions of this section shall make application with the secretary of the Tennessee retirement system within ninety (90) days after the passage of this section and shall pay into the state retirement system an amount to be determined by the retirement board, based upon the salary for the time served as sheriff.
T.C.A. § 8-3421