Manley joined the Austin Police Department in 1990 and was named chief of police in 2018 after serving nearly two years as interim chief. In his nearly 30 years with the department, he has served in and led many areas of the department, including narcotics, child abuse, homicide and special operations and homeland security. As chief, Manley leads a department of 1,900 sworn officers with a budget of $422 million.