Division Chief Dan McMillan began his career with the Douglas County Sheriff’s Office in 1989 as a Law Enforcement Explorer. Throughout his career, he has served as a deputy in the Detentions and Patrol Divisions, a Field Training Officer, a Corporal, and an Investigator. He has also held the rank of Sergeant in the Patrol Division and served as a Lieutenant assigned to Patrol, Detentions, Investigations (Impact Unit and Major Crimes Unit), and Professional Standards (Internal Affairs and Training Sections.)

In 2022, he was assigned as the Patrol Division Captain, overseeing patrol services for the Town of Larkspur, the City of Castle Pines, and the Pike National Forest.  Additionally, he had oversight of Special Teams, the Traffic Enforcement Section, the Community Response Team (CRT), and the Homeless Engagement Assistance and Resource Team (HEART).

He now serves as the Division Chief of the Investigations Division overseeing Persons Crimes, Property Crimes, Special Victims Unit (SVU), Financial Crimes Unit (FCU), Task Force Officers, Victim Assistance Advocates, Crime Lab, and Evidence and Property Section. His leadership ensures effective case management, investigative operations, and support for victims of serious crimes.

Previously, Division Chief McMillan served as the SWAT Commander for the Douglas County Regional Special Weapons and Tactics (SWAT) Team for over twenty years. During his tenure, he was instrumental in regionalizing the team to include all three municipal law enforcement agencies, enhancing resource-sharing and cost efficiency for Douglas County. He also expanded the Tactical Emergency Medical Support (TEMS) program in partnership with South Metro Fire Rescue, improving its ability to serve the community.

He has been an active member of the North Central Region (NCR) and Denver Urban Area Security Initiative (UASI) Public Safety and Security Sub-Committee since 2008. In 2019, he received a Lifetime Achievement Award from the Rocky Mountain Tactical Team Association (RMTTA) and continues to serve as an RMTTA Advisory Board Member.

Division Chief McMillan has attended numerous leadership development programs and, in 2008, graduated from the Northwestern University School of Police Staff and Command, Class 253.