Major Allman was born on 23 March 1993 in Joplin, Missouri. He attended high school in Topeka, Kansas and graduated from Washburn Rural High School in 2011. He attended the University of Kansas and graduated in 2015 with a bachelor of science in political science. After commissioning in May 2015, Second Lieutenant Allman reported to The Basic School in September 2015 and graduated in March 2016. He subsequently reported to Marine Detachment Fort Sill, Oklahoma and attended Field Artillery Officer Basic Course, graduating on the Commandant's Honor Roll in September 2016.
In September 2016, Second Lieutenant Allman reported to 2nd Battalion, 10th Marine Regiment and was assigned to Battery E. From September 2016 to June 2017, he served as the Battery Fire Direction Officer and Headquarters Platoon Commander. In July 2017, First Lieutenant Allman was assigned to Battery G, 2nd Battalion, 10th Marines and served as the Guns Platoon Commander until November 2017. In December 2017, he was reassigned as the Battery G Executive Officer. In May 2018, the Marines of Battery G attached to Battalion Landing Team 1/2 and deployed in December 2018 with the 22d Marine Expeditionary Unit. From January to April 2019, Battery G supported combat operations in Northern Syria within OPERATION INHERENT RESOLVE before redeploying with the 22d Marine Expeditionary Unit in July 2019.
In September 2019, Captain Allman reported to Marine Corps Recruit Depot, Parris Island. Captain Allman was assigned to Company C, 1st Recruit Training Battalion and served as a Series Commander for four training cycles. In February 2021, Captain Allman was assigned to Company D and served as the Company Executive Officer and a Series Commander for two and a half training cycles. In October 2021, Captain Allman was assigned to Company B and served as a Company Commander for two training cycles.
In July 2022, Captain Allman reported to Expeditionary Warfare School and graduated in May 2023. Upon graduation, Captain Allman reported to Officer Candidate School and served as an Academics Instructor within the summer augment program until August 2023.
In September 2023, Captain Allman reported to 1st Battalion, 10th Marines and was assigned as the Battery D Commander. He deployed for training to Avon Park, Florida for Exercise JADED THUNDER 24.1 in March 2024 and Service Level Training Exercise 24.5 in 29 Palms, California from July to August 2024. In September 2023, Major Allman was reassigned as the Battalion Logistics Officer and served in that capacity until May 2024.
In June 2024, Major Allman reported to Rensselaer Polytechnic Institute Naval ROTC in Troy, NY where he currently serves as the Executive Officer and Marine Officer Instructor.
Major Allman is a graduate of Expeditionary Warfare School (resident and non-resident), Fire Support Coordination Course, and Joint Fires Observe Course. He is currently completing his second and final year of Marine Corps Command and Staff College (non-resident) while concurrently finishing a master's degree in Leadership Studies from Marshall University.
Major Allman has been married to his wife Jen Allman since June 2022. They have two sons: Elijah (born 2023) and Josiah (born 2025).