Biloxi Public Works Director Dan Gaillet is resigning effective Jan. 4 after two years on the job.
He was hired by Mayor A.J. Holloway in December 2013, soon after his son Robert was seriously injured in an accident in November 2013.
Gaillet said he plans to return to Jackson to closely oversee his son's continued treatment.
"As difficult as it is to say goodbye, I know I'm leaving the city in good hands and am excited about the city's future and the continued healing of the city's infrastructure."
The mayor and council last week indicated that Gaillet would be the choice to head a new engineering department that would oversee Biloxi's $365 million infrastructure project.
Biloxi Mayor Andrew "FoFo" Gilich said he plans to name an acting public works director before nominating a full-time director.
"Dan Gaillet did a lot of great things during his time in Biloxi, and our Public Works Department is better today because of him," Gilich said. "He instilled professional standards of operation that will continue to help the department better serve our citizens."
During his two years in Biloxi, he oversaw the designation of bike lanes throughout the city and hundreds of parking spaces downtown near MGM Park. He also helped design new sidewalks on Atkinson Road near Hiller Park.