In 2004, he reported to the 3d Fleet Anti-Terrorism Security Team (FAST) Company where he served as Assistant Platoon Commander and Platoon Commander for 3rd Platoon and Platoon Commander 5th Platoon. He participated in Operation Unified Assistance in response to the 2004 Boxing Day Tsunami and performed multiple missions in support of; Commander, 7th Fleet, Commander, Puget Sound Naval Shipyard, and JTF-Guantanamo. Following his platoon assignments Grasso served as the Executive Officer, 3D FAST Company until 2007.
In 2007, he attended the Expeditionary Warfare School in Quantico, Virginia. After graduating in 2008, he received orders to 1st Battalion, 12th Marine Regiment. He assumed duties as the Assistant Operations Officer and deployed with 1st Battalion, 12th Marine Regiment to Operation Iraqi Freedom as Task Force Military Police, II Marine Expeditionary Force. In June of 2009, he took command of Battery A, 1st Battalion, 12th Marine Regiment until June of 2010.
In July of 2010 he was transferred to Marine Forces Pacific Command to serve as the Australia, New Zealand, South Pacific Islands and Mongolia Desk Officer, Policy and International Affairs Branch in the G-5. During this tour, he developed engagement and activities with partner nations in the Asian Pacific and earned the additional specialty of Southeast Asia Regional Affairs Officer. He was then assigned as a Foreign Military Exchange student in the New Zealand Command and Staff College where he also studied International Security Studies, Massey University, graduating in December 2012.
From January 2013 to July 2016 he was assigned as the Executive Assistant to the Political Advisor for the Vice Chairman of the Joint Chiefs of Staff and Supreme Allied Commander Transformation NATO. Following his Joint Staff tour he completed Joint and Combined Warfighting School and received his Joint Qualification. In July of 2016 he transferred to 1st Battalion, 12th Marine Regiment, Marine Corps Base Hawaii, Kaneohe and served as Executive Officer until July of 2017. From July 2017 until July 2018 he was assigned to Marine Air Ground Task Force Staff Training Program, Fires and Targeting Instructor. From June 2018 to July 2020, he was the Inspector-Instructor, 4th Air Naval Gunfire Liaison Company, West Palm Beach, Florida. From there he was a student at National Defense University and graduated from the Eisenhower School for National Strategy and Resource Strategy, Washington D.C. In June of 2021 and was assigned to Joint Task Force- Civil Support, and served as Director of Operations until January of 2023. Lieutenant Colonel Grasso now serves as the Chief of Staff for JTF-CS.
His personal awards include the Defense Meritorious Service Medal, Meritorious Service Medal (Gold Star in lieu of 3rd award), Navy and Marine Corps Commendation Medal (Gold Star in lieu of 2nd award), the Navy and Marine Corps Achievement Medal with Combat Distinguishing Device (Gold Star in lieu of 3rd award), the Humanitarian Service Medal, and the Combat Action Ribbon.