Barry agreed to reimburse the city $10,000 and serve three years probation, according to local media reports. The resignation and plea comes amid investigations into her affair with her former bodyguard police Sgt. Rob Forrest.
In a statement, Barry said while her time as "mayor concludes today," her "unwavering love and sincere affection for this wonderful city and its great people shall never come to an end."
"It's a continued climb that I will watch, but I will watch as a private citizen, and I will be tremendously proud nonetheless," she said, adding she hoped that her "own actions will not tarnish or otherwise detract" from the work going on in the city.
The resignation puts Vice Mayor David Briley into the mayor's post.
Barry, a Democrat, was elected in 2015.
The Tennessee Bureau of Investigation had been investigating Barry's relationship with Forrest since the married mayor confirmed this year the two had an affair in 2016. Forrest, who is also married, retired Jan. 17 after reports of the relationship emerged.
Last week, a Nashville judge issued a search warrant seeking possession of the mayor's cellphone.
TBI claimed the affair had occurred while the two were traveling on official business and Forrest was being paid by the city. Among the evidence cited by TBI was nude photos of a woman taken from Forrest's phone.
According to the Tennessean, Barry and Forrest attended 10 city-funded trips by themselves, including conferences to Paris, Greece and Washington, D.C. Forrest earned $173,843 in overtime from July 2015 to January of this year, records show.
(c)2018 Alabama Media Group, Birmingham
