Captain Mattei is a native of McKinney, Texas and was commissioned as a Second Lieutenant in the United States Marine Corps in 2019.
Following commissioning, he attended The Basic School from October 2019 to March 2020 and subsequently completed the Infantry Officer Course from June to August 2020. In September 2020, he reported to 3d Battalion, 2d Marines, where he served as a Rifle Platoon Commander with Company L.
In 2022, he deployed to Okinawa, Japan, as part of the Unit Deployment Program (UDP). Upon return from deployment, he attended the Weapons and Tactics Instructor Course. In January 2023, he assumed command of Weapons Company, 3rd Battalion, 2nd Marines. He ended his active duty service in January 2024.
In February 2025, Captain Mattei reported to Company C, 1st Battalion, 24th Marines, where he served as the Weapons Platoon Commander and Executive Officer.
In March 2026, he assumed command of the company and currently serves as its Commanding Officer.
Captain Mattei's personal awards include the Navy and Marine Corps Commendation Medal.