Sergeant Major Mingledorff enlisted in the Marine Corps on September 25, 1985 and attended Recruit Training at Marine Corps Recruit Depot, Parris Island, South Carolina. In 1986 he completed training as an Infantry Mortarman, School of Infantry, Camp Geiger, North Carolina and was assigned to Weapons Company, 81mm Mortar Platoon, 1st Battalion, 6th Marine Regiment at Camp LeJeune. While assigned to 6th Marines, he deployed with the 22nd MAU (SOC) to the Mediterranean as a part of Marine Amphibious Ready Group (MARG 1-87) and a UDP to Okinawa, Japan.
 
In February 1988, he attended and completed Marine Security Guard School at Quantico, Virginia. Upon graduation, he was assigned to MSG Detachment, American Embassy in Prague, Czechoslovakia and the Consulate General in Rio de Janerio, Brazil.

In December 1991, he left active duty to pursue a career in Law Enforcement. He was transferred to the Selected Marine Corps Reserve where he joined India Company, 3rd Battalion, 24th Marine Regiment in Nashville, Tennessee, serving in billets as 60mm Mortar Section Leader, Platoon Sergeant, Platoon Commander, and Company Gunnery Sergeant. In January 2004, he was activated and deployed to Iraq in support of Operation Iraqi Freedom II.

In February 2005, he was promoted to the rank of First Sergeant and transferred to Alpha Company, 4th Tank Battalion, Fort Knox, Kentucky, where he served as Company First Sergeant.

In June 2008, he was promoted to Sergeant Major and assumed the duties as Battalion Sergeant Major, 4th Assault Amphibian Battalion, Tampa, Florida.

In September 2011, he assumed the duties of Group Sergeant Major, Marine Wing Support Group-47, 4th Marine Aircraft Wing, Mt. Clemens, MI.

In August 2012, he was assigned as Group Sergeant Major, Marine Aircraft Group 49, Joint Base McGuire-Dix-Lakehurst, New Jersey.

His personal decorations include the Meritorious Service Medal, Navy and Marine Corps Commendation Medal, Navy and Marine Corps Achievement Medal with 2 gold stars in lieu of third award, Marine Corps Outstanding Volunteer Service Medal, and the Combat Action Ribbon.