Hagler first served as a police officer with the Bessemer Police Department. He joined Hueytown in 1991 and rose to become the department's criminal investigator. He became the acting chief when Doug McBee resigned in October 2007. He was confirmed as permanent chief by Mayor Delor Baumann in December 2007 and sworn in by District Court judge Jill Ganus on December 18.
- Gordon, Robert K. (December 4, 2007) "Hueytown: Hagler promoted to police chief." Birmingham News.