Sergeant Major Gerhardt entered the United States Marine Corps in May 1994 out of Jacksonville, FL and reported to Marine Corps Recruit Depot, Parris Island, SC for recruit training. Private Gerhardt graduated from Recruit Training at 1st Battalion Company B, Parris Island, South Carolina in July 1994. He attended Infantry Training at Infantry Training Battalion at Camp Geiger, North Carolina for further training as a rifleman 0311. Upon completion of training, he received orders to Marine Corps security Forces Battalion in Dam Neck, Virginia for training as a Marine Forces Security Guard. Upon completion of training he was assigned to Marine Corps Security Forces, Naval Submarine Base Bangor, Washington for duty as a security guard from January 1995-January 1997.
In March 1997, Lance Corporal Gerhardt transferred to 3D Battalion 6th Marines where he was promoted to the rank of Corporal before deploying to the Mediterranean with the 24 MEU and supported Operation Southern Watch. Upon his return from the 24 MEU, Corporal Gerhardt was promoted to the rank of Sergeant and transferred to 3D Battalion 8th Marines in December 1998. There he served as infantry squad leader while deployed on the 26 MEU in support of Operations Shining Hope, Allied Force, and Joint Guardian in the Adriatic Sea in support of combat operations in Kosovo. Upon returning to the United States he received orders and reported to Headquarters and Service Battalion Marine Corps Base Quantico, Virginia for duty in December 1999.
Sergeant Gerhardt served as the base education assistant and Marine Battle Skills Training Instructor from December 1999-May 2002 where he received orders to recruiter school in San Diego, California. Upon graduating school he reported for duty as a canvassing recruiter with 1st Marine Corps district in Garden City, New York where he was promoted to the rank of Staff Sergeant. From August 2002 thru May 2005, Staff Sergeant Gerhardt served as a canvassing recruiter in RSS Hicksville, New York and Staff Non-Commissioned Officer in Charge of RSS Smithtown, New York. Upon successful completion of recruiting duty he received orders in July 2005 to 3D Battalion 1st Marines for duty where he was promoted to the rank of Gunnery Sergeant.
In September 2005-March 2006 he deployed to Southwest Asia Iraq during OIF 5-7 and served as Infantry Platoon Sergeant for Combined Anti-Armor Team 1. In 2007 Gunnery Sergeant Gerhardt deployed with 3D Battalion 1st Marines on the 13 MEU in support of OIF 6-8. Upon return to the United States he received orders in April 2008 to School of Infantry West Advanced Infantry Training Battalion permanent personnel for duty as the Assistant Operations Chief. In April 2008 he reported to Marine Combat Instructor Course as a student. Upon graduating school Gunnery Sergeant Gerhardt reported to Advanced Infantry Training Battalion where he served in the billets of Assistant Operations Chief and Company Gunnery Sergeant of Infantry Unit Leader Training Company School of Infantry West where he was promoted to the rank of First Sergeant in April 2010.
First Sergeant Gerhardt reported for duty with 8th Communication Battalion in May 2010 where he served as Company B First Sergeant and deployed to Afghanistan in support of OEF from July 2011-January 2012. Upon return he was assigned to General Support Company for duty as Company First Sergeant. In September 2013 he received orders to 3D Battalion 6th Marines where he served as Weapons Company First Sergeant and deployed with the 24 MEU in the Red Sea. Upon returning he was assigned as the Headquarters and Service Company First Sergeant.
In January 2016 Sergeant Major Gerhardt was promoted to his current rank and reported for duty as the Squadron Sergeant Major for Marine Wing Support Squadron-271, Marine Aviation Group 14, 2d Marine Aircraft Wing, Cherry Point, North Carolina where he served until December 2017. In January 2018, Sergeant Major Gerhardt reported for duty as the Battalion Sergeant Major for 1st Battalion 25th Marines, 25th Marine Regiment, 4th Marine Division.
His awards include the Meritorious Service Medal, Navy and Marine Corps Commendation Medal with three gold stars in lieu of fourth award, Navy and Marine Corps Achievement Medal with two gold stars in lieu of third award, Combat Action ribbon with gold star, Good Conduct Medal with silver star and one bronze star, Global War on Terrorism Expeditionary Medal, Global War on Terrorism Service Medal, Iraq Campaign Medal with two bronze stars, Afghanistan Campaign Medal with one bronze star. Sergeant Major Gerhardt also holds a Bachelor of Science in Management.