Brookes is the son of a career naval officer and is a 1987 graduate of California Polytechnic State University, where he received a Bachelor of Arts in Political Science.

He also holds a Master of Arts in National Security Affairs from the Naval Postgraduate School in Monterey, California.

Brookes attended Navy Officer Candidate School in Newport, Rhode Island and was commissioned in March 1989.

Brookes’ operational tours include imagery intelligence officer for the "Checkmates" of Fighter Squadron (VF) 211 embarked aboard USS Nimitz (CVN-68); assistant intelligence officer (N21) for Cruiser-Destroyer Group 1, embarked aboard USS Constellation (CV-64); assistant chief of staff for intelligence (N2) for Carrier Strike Group 7, embarked aboard USS Ronald Reagan (CVN-76); deputy director of intelligence (DJ2) for Joint Special Operations Command, where he deployed to Bagram, Afghanistan as director of intelligence (J2) for a joint special operations task force; and information warfare commander for Carrier Strike Group One, embarked aboard USS Carl Vinson (CVN-70).

Ashore, Brookes served as international programs officer for N2 Directorate, U.S. Pacific Fleet; officer-in-charge (OIC), Maritime Watch, Joint Forces Intelligence Command; intelligence operations and plans officer, Naval Special Warfare Command, where he augmented a joint special operations task force in Kabul, Afghanistan; and Deputy Director of Intelligence (DDI), National Joint Operations Intelligence Center (NJOIC) for the Joint Chiefs of Staff.