Major Pierre K. Butler completed the Basic Officer's Course and the Combat Engineer Officer's Course in 2015. His first duty assignment was with 9th Engineer Support Battalion in Okinawa, Japan, where he initially served as the Battalion Training Officer before transferring to Engineer Company A as a Platoon Commander. There, he participated in Exercise Balikatan 16 and was responsible for leading combined and joint civic assistance construction projects in the Philippines. Upon returning from the Philippines, First Lieutenant Butler was reassigned as the Executive Officer for Engineer Company B, where he participated in Exercises Ulchi-Freedom Guardian, Blue Chromite, and Philippine Amphibious Landing Exercise 33. In June 2017, First Lieutenant Butler concluded his time at 9th ESB as the Executive Officer for Engineer Support Company.
In June 2017, First Lieutenant Butler reported to Headquarters, United States Central Command aboard MacDill Air Force Base in Tampa, Florida. Serving within the Operations Directorate's Joint Security Office, First Lieutenant Butler filled several staff and action officer roles as the lead Force Protection Engineer, Security Engineering and Supporting Infrastructure Assessor, and Mission Assurance Section OIC. In November 2017, he was promoted to Captain. In addition to direct engagements with host nation security forces throughout the Central region, the Joint Staff, Office of the Secretary of Defense, and other government agencies, Captain Butler and his team completed multiple sensitive missions throughout the CENTCOM area of responsibility in support of named operations.
From July 2020 to May 2021, Captain Butler attended Expeditionary Warfare School in Quantico. Immediately following graduation, Captain Butler reported to Marine Wing Support Squadron-272 aboard Marine Corps Air Station New River to serve as the Engineer Company Commander. In October 2021, he completed Weapons and Tactics Instructor Course aboard Marine Corps Air Station Yuma, earning the 7077 Military Occupational Specialty. From January to April 2022, Captain Butler led a task-organized company of 130 Marines and Sailors in Norway as part of Exercise Cold Response. In August 2022, he relinquished command of Engineer Company and assumed duties as the Assistant Squadron Operations Officer. From January through March 2023, Captain Butler managed all Marine Air Control Group activities and the Aviation Ground Support Operations Center during Service-Level Training Exercise 2-23 aboard the Marine Corps Air-Ground Combat Center, Twentynine Palms. He was promoted to his current rank in April 2023.
In August 2023, Major Butler reported to Navy Expeditionary Combat Command in Little Creek, Virginia, as the Force Marine Officer and a member of the N5 (Strategy, Plans, and Concepts). As the sole active duty Marine assigned to the command, Major Butler provided Marine Corps perspectives to emerging doctrine for the Navy's expeditionary combat forces, including construction, explosive ordnance disposal, and logistics support organizations.
In April 2025, Major Butler detached from NECC and reported to 8th Engineer Support Battalion the following month. Major Butler is currently serving as the executive officer for 8th Engineer Support Battalion.
Major Butler holds a Bachelor of Arts in International Studies with a Minor in French from Norwich University (NUCC '12). In addition to other schools and training, he has completed the USAID Joint Humanitarian Operations Course, the US Army Military Police School's Antiterrorism Officer Basic and Advanced Courses, the Joint Engineer Operations Course, and Marine Corps Command and Staff College (Distance Education Program). His personal awards include the Defense Meritorious Service Medal, the Meritorious Service Medal, the Navy and Marine Corps Commendation Medal, the Joint Service Achievement Medal, and the Navy and Marine Corps Achievement Medal.