Master chief petty officer

Master chief petty officer (MCPO) is an enlisted naval rate, a type of military rank used by the service organizations of different cultures. As a traditional naval grade, MCPO is the most senior grade of chief petty officer, and is almost the highest non-commissioned officer grade in organizations like Starfleet and the US Navy. In comparison to infantry ranking systems, this rate is approximately equivalent to the most senior sergeant grade, such as Sergeant-Major. Personnel of this grade can be addressed simply as chief (or more properly, "master chief"), and sometimes by their job title, such as "master chief specialist."

While nominally subordinate to all commissioned officers, master chiefs wield far more influence and authority than most junior officers and act as mentors and advisors to senior officers. Master chiefs have decades of practical experience and are an indispensable source of technical skill and leadership on Starfleet vessels.

When there are individual grades of chief petty officers, senior chief petty officer (SCPO) is subordinate to MCPO.

In 2286, when a probe projecting humpback whale signals threatened to destroy Earth, MCPO Janice Rand was one of the personnel in Admiral Cartwright's command area. (Star Trek IV: The Voyage Home)

In addition, there exist three other grades of master chief in Starfleet: Command Master Chief Petty Officer (CMCPO), Fleet Master Chief Petty Officer (FMCPO) and Master Chief Petty Officer of Starfleet (MCPOSF). The first is the senior enlisted man in a Starfleet command structure, the second is the highest enlisted man in a fleet and the last is the senior enlisted man in all of Starfleet.

Starfleet insignia

22nd century	2230s

2250s	2265-2270s	Early 2270s	Late 2270s-2350s

2350s-2360s	2360s-2370s service uniform	2360s-2370s duty uniform	2370s-2380s

Early 2380s	Mid 2380s	2390s
File:MCPO (early 2380s).png File:Red (early 2380s).png	File:MCPO (mid 2380s).png File:Red (mid 2380s).png	File:MCPO (2390s).png File:Red (2390s).png

Alternate realities

2250s	2380s-2400s	2390s	29th century

Non-Starfleet insignia

Klingon Navy	Lyran Starfleet

		Enlisted ranks					Etc	Officer ranks						Flag ranks
Starfleet Officers Enlisted Misc.		CR CA CN	PO3 PO2 PO1	CPO	SCPO	MCPO CMCPO FMCPO MCPOSF	WO CDT MID REC	ENS	LTJG	LT	LCDR	CDR	CAPT FCAPT	CDRE RDML RADM		VADM	ADM	FADM
Klingon Defense Force (Ground forces & navy)		Bekk	Cpl	Sgt	MSgt	SgtMaj		2nd Lt	1st Lt	Capt (HoH)	Maj	LtCol	Col	Brig ('ech)		LtGen	Gen (Sa')
			PO2	PO1	CPO	MCPO		ENS	LTJG	LT (Sogh)	LCDR	CDR (la')	CAPT (HoD)	CDRE (totlh)		VADM	ADM
Kai Imperium		TRN MNX IMUN	LGN3 LGN2 LGN1	CLGN	CEN	SCEN		PVT	PRN		OP	TRB VIC	PR	PTR		MST	LEG	IMP
Kellarian System Defense Force (Navy & Ground forces) (Star Trek: Remington)		CR CN	PO2 PO1	CPO	SCPO	MCPO		ENS	SLT	LT	SCDR	CDR	CAPT	CDRE	VADM		ADM	FADM
		PVT PFC	CPL SGT	SSG	MSG	SGM		3LT	2LT	1LT	MAJ	LTCOL	COL	MGEN	LGEN		GEN	CGEN
Lyran ranks		CR CN	PO2 PO1	CPO	SCPO	MCPO	CDT	ENS	LTJG	LT	LCDR	CDR	CAPT FCAPT	CDRE	SCDRE	VADM	COUNT	DUKE KING
So'ja High Command		REC CN PVT	PO3 PO2 PO1	CPO	MC			CPL	SGT	LT	MAJ	LTCOL	COL	ADM			MADM	SADM

External link

Master chief petty officer article at Memory Alpha, the canon Star Trek wiki.