What exactly is the difference between a Master Sergeant and a 1st Sergeant? Is one technically higher than the other?

yes, they get paid the same as a E8, but 1SG is a position of leadership like the CO, so yes a 1SG outranks a MSG.

It's kinda like SPC. And CPL.

One usually is an office worker while the other is not. The 1st Sgt is usually out with the company. While the MSG is in an office doing all the paper work or with the Cpt or another officer.

Both are Pay grade E-8. The First Sergeant is a Leadership position at the company level. Master Sargeants are generally more staff related position. The MSG may be senior NCO like an Operatons Sergeant in a Detachment or Battalion or higher Staff section. Once a First Sergeant moves out of the position he becomes a master sergeant. There is a similar situation with Sergeant Majors. There are Command Sergeant Majors and Sergeant Majors. The CSM is a command position. Both are the right hands of their respective commander and generally speak with the authority of the commander.

A First Sargent runs the Company, and is the Senior Enlisted Advisor to the Company Commander. A Master Sargent might be in charge of one of the Battalion's "S" sections, or for example When I was stationed at Fort Lee as an instructor, The Petroleum Supply Specalist School had a Sargent Major, and a Master Sargent as his second.

Similar to what has already been said the same difference as a SPC and a CPL only at a higher level. The biggest difference is that as a CPL, the Department of the Army can appoint you the rank of CPL which you would not lose unless you are punished and go back to being a SPC, where as a MSG when appointed to the rank and position of 1SG and they finish that assignment and move on to another unit they go back automatically to being a MSG. There isn't a permanent assignment to being a 1SG. Each unit they go to has to appoint them to the position. Also a SFC Promotable can be "frocked" to the position and wear the rank of a 1SG without the pay of an E-8 but all the duties and responsibilities of the position and the rank attached to it.

Your curiosity is not without merit. However, you may find your answer locally from your unit and within your NCO chain.

I have a bit to add myself, Special Forces, Special Mission Units & Special Operations work at a different structure. Companys are managed by a SGM and Team Sergeants & Team Leaders are a MSG. There are very few 1SG slots in such units and are assigned at a Detachment level or at a Special Warfare School with the 1SG duties. NCOIC are a SGM position. The 1SG are considered staff position and a MSG is operational. The CSM positions is only at Detachment or Group positions. However, promotion wise the 1SG has higher considerations at promotion boards. Most MSGs prefer to remain on teams which the slot for 1SG is a ticket puncher to CSM. That was more or less the structure in my day but things change. Most of which I believe is the same today.

Command authority

A Master Sergeant is an E-8 and always will be; despite their role within a unit. While the First Sergeant Role is and E-8 position, it may be filled by someone of a lower rank. As an E-6 (Staff Sergeant) I served as the Company First Sergeant when my First Sergeant allowed all of the Comapny's E-7 take leave at the same time along with himself. I also served as Company First Sergeant as an E-7 (Sergeant First Class) when my First Sergeant was away at First Sergeants School. Both were temporary assignments of course. Technically, the First Sergeant Position is above the Master Sergeant within the company. But a Temporary First Sergeant better beware if he/she pushes a Master Sergeant around with her/his temporary position.

SGT Gunderson,
I believe that you are mistaken for this is simply a training issue for the majority of Command Staff. I am the 1SG of a Field Artillery Battery but am currently deployed as part of a Joint Staff. The 2nd day on ground, I took off the diamond and am referred to as “Master Sergeant” by all the Navy and Air Force personnel on ground. They do not know that I am a First Seargeant and when I attempt to explain to them that when I came to a “Staff” position, I lose the diamond for I am not part of the “Command Team”.
His Drill Sergeants did not fail him for it is something you learn after a while after you start to earn your technical and tactical experience.

I find it odd that wasn't explained in basic.

Go find yourself a MSG and ask. Go straight to the source. It's the quickest way to get the answer. Don't be a pussy, SPC. Or be a Pussy Specialist. I don't fucking care, just get an exhaust sample of the commanders track over to the motorpool.

1st Sgt is Top Gun by the book by designated authority in the same manner Old School 'Green Tab' NCO may command any US ARMY combat formation; nevertheless, natural leaders sometimes emerge. The NCO is the backbone of the US ARMY. Initiative without orders must be requisite. For example, a E-4 once commanded Lt. Col. Andres' 1/33 AR 2 BDE 3 AD SPEARHEAD.

What I understand is that the Master Segeant is a subject matter expert albeit enlisted advisor, unlike a warrant officer. A Sergeant Major and First Sergeant is a manpower manager. They have similar skillsets when it applies to leadership but billet wise they serve one or the other purpose as mentioned earlier.

Yes, First Sergeants run the Army.

Technically they are the same except for the Diamond . It signifies that diamond is in charge of a Company... as a Master sergeant just assist anyway they can .....

Both are Senior Non-Commissioned Officers. However, the First Sergeant requires the rank of a MSgt as a minimum. It’s a dictinctive senior position in an organization. The 1Sgt is solely charged with managing the welfare of the enlisted personnel in the organization they are assigned, on behalf of the Unit Commander.

Sorry I hit E-9 rather than E-8. They are bothe senior enlisted soldiers but the 1st Sgt would be considered the NCOIC in this case even though they are both E-8 in Rank. I apologize for the first post, my damn fingers are too big for these letters and numbers. The eyesight of this old man doesn’t help either....

I hope this helps....

Yes, 1st Sgt is an E-9 which is a higher rank and the highest rank of an Enlisted person...