[1] As Inspector General, Castellvi oversaw matters of institutional integrity, discipline and combat readiness in the Corps, maintaining credibility through impartial and independent inspections, assessments, inquiries, investigations, teaching, and training.

Castellvi relieved Zavala on 7 May 2019 for "loss of trust and confidence" in the commander's ability to lead the battalion.

[10] Castellvi was suspended from all current duties on 1 May 2021 on orders from David H. Berger, Commandant of the Marine Corps, based on an investigation into his responsibility for an AAV mishap at Camp Pendleton, when 8 Marines and a Navy Corpsman drowned in a preventable "accident" on 30 July 2020.

[11][3] In June 2021, Marine spokespersons reported that Castellvi had been permanently relieved of duty as Inspector General and counselled by the Commandant, rendering him likely ineligible for promotion to higher rank.

[12][13] Major General Castellvi is a graduate of the University of Illinois where he earned his Marine Corps commission through the NROTC program.