Mr. Castellano is currently serving as the Executive Director, Munitions Engineering and Technology Center (METC) at the U.S. Army Combat Capabilities Development Command Armaments Center (DEVCOM AC), Picatinny Arsenal, NJ. Appointed by the Secretary of the Army in September 2016, Mr. Castellano assumed his new role leading a world-class research and engineering organization responsible for the development, systems integration, and rapid fielding of munition-based armament systems for the Army, Marine Corps, and Special Forces. Together with a competency team of over 1200, products and services provided span a wide spectrum of advanced, lethal/non-lethal small, medium, and large caliber munitions, as well as advanced component technologies including warheads, fuzing, sensors, energetics, and non-traditional nano structures. Mr. Castellano is also responsible for safety, environmental and technical efficacy of over 250 unique, hi-tech laboratories, small pilot operations, indoor/outdoor experimentation ranges, rapid prototyping and additive manufacturing capabilities, and other specialty laboratories valued in the hundreds of millions.

Mr. Castellano was appointed by the HON Donald H. Rumsfeld, Secretary of Defense, to the rank of Senior Executive Service (Tier 2) in December 2003. He served the Office of the Secretary of Defense as Deputy Director, Systems Engineering (SE), and within 2 years was performing the duties of the Director SE (Tier 3) as principal acquisition technical advisor to the Under Secretary of Defense (AT&L), Assistant Secretary of Defense (NII), Under Secretary of Defense for Intelligence, and other senior acquisition officials on matters relating to strategic and tactical mission success. In this capacity, he reported to the Defense Acquisition Board (DAB) for Major Defense Acquisition Programs (MDAP) and was a voting member on the Information Technology Acquisition Board (ITAB) for Major Automated Information Systems (MAIS).
Career honors include the Presidential Rank Award (Meritorious), Secretary of Defense Medal (Exceptional Civilian Service), NATO Certificate of Recognition (Outstanding Service), and prestigious NDIA awards for Systems Engineering Excellence, Firepower Development, and John A. Ulrich Lifetime Achievement award.