Director Marilyn Drew said she would fight the dismissal.
Ellis also placed Al Sheppard, the acting deputy director of recreation services, on paid administrative leave. Ellis said he would immediately search for a new director of parks and recreation.
The move came after a weekend of outcry from parents of youths in the DeKalb Swim League, who learned last week they were never entered in the annual GRPA competition.
"In an attempt to correct the wrongs that have occurred in this regard, I am addressing the failings on the part of the Parks and Recreation Department officials," Ellis said in a letter addressed Monday to Dodson. "DeKalb's children should not be punished for these officials' lack of response."
Drew, reached at her home late Monday night, declined to discuss the issues Ellis wrote about. But the eight-year DeKalb County employee said she wouldn't give up her job easily.
"As a merit-protected employee, I will avail myself to the appeal process," Drew said.
Staff writer Katie Leslie contributed to this article.