Major Greg Lees began his law enforcement career with the Broward Sheriff's Office in 1983 as a community service aide. Soon after, he attended the police academy and became a patrol deputy in unincorporated Pompano Beach. Next, Major Lees transferred to the Strategic Investigations Division, where he investigated drug trafficking crimes. He was later assigned to the Drug Enforcement Administration as a task force officer, investigating international drug trafficking organizations, specifically the Cali Cartel.  

Major Lees also served as a detective in Port Everglades and was promoted to detective sergeant in charge of the Gang Investigations Unit, where he oversaw the Gang Unit and was the Multi-Agency Gang Task Force Coordinator and later to the Pompano Beach District as the street crimes sergeant. He was then promoted to lieutenant, serving as the executive officer in Area 2, Pompano Beach, Executive Officer of the Specialized Operational Services Division, and the Strategic Investigations Division, where he supervised detectives assigned to the FBI Joint Terrorism Task Force, BSO's Office of Domestic Preparedness and Bomb Squad.

While serving in these various assignments, Major Lees spent over 30 years on the BSO SWAT Team as an Operator, Assistance Team Leader and Team Leader before becoming the SWAT Commander.  Major Lees has participated in over 1500 tactical operations, including multiple large-scale critical incidents, hostage situations, warrant service, protective service operations and barricaded criminal suspects.

Major Lees also spent time as the Deputy Chief of Police in the city of Coconut Creek before returning to the BSO family in 2019, where he once again served as SWAT Commander before moving on to the Special Patrol Division, supervising Marine, Aviation, K9, Dive Rescue Team and the Regional Traffic Unit. He was promoted to major in March 2023 and took command of the Special Operations Bureau, which consists of the Special Patrol Division and the Tactical Operations Division.

Major Lees graduated from Western Carolina University with a Bachelor of Science in Criminal Justice. He is also a graduate of the Florida Department of Law Enforcement (FDLE), Chief Executive Seminar, Florida Chiefs of Police Association (FPCA) Future Chiefs Seminar, FBI Federal Executive Development Seminar, and the FBI National Academy (Session 259), where he currently serves as an FBINAA area representative. Major Lees also serves as the police liaison for the Hundred Club of Broward County and is a member of the National Tactical Officers Association, Broward Chief of Police Association and Airborne Public Safety Association.