Yes, you will need to meet qualifications and licensing requirements to perform 'Debt Collection' activities for 3rd parties in Tennessee.
For example, you (even as a single employee working from home) will have to meet the following:
"License Requirements:
T. C. A. 62-20-108 (a) (1) Every Collection Service shall have, for each location at which it conducts business, a location manager who has submitted an application on a form prescribed by the board, and has demonstrated to the satisfaction of the board that he/she has passed an examination approved by the board. An applicant must have (1) one year experience within a three year period of the date the examination in a business which is governedbby laws similar to those laws which govern a licensed collection service, including but not limited to, the Fair Debt Collection Practices Act."
Here is a link to the regulatory agency involved:
http://www.state.tn.us/commerce/collect.htm