Where can I find the regulatory guidance for the proper way for a commissioned officer to address an NCO?

In the Navy its either Petty Officer or Chief. Ive had officer who addressed me by my first name in private, because of knowing them, because either having served with before, or them being prior enlisted.. But this is something that should never been done in public. There is a line between officer and enlisted and I believe calling an NCO by his first name in public, crosses that line and is a bad example for junior troops

This is a first for me. To this day I can't get officers I worked with to call me by my first name. They all still call me Chief. While still in the Air Force I had some officers try to call me by my first name. I usually requested they address me by my proper title. That usually solved it. A few called me Scotty, when in private, but they were usually Commanders who I respected greatly & it did not bother me. Never in front of the Airmen. Sounds like an officer who doesn't realize the effort & sacrifice it takes to earn rank.

Speak to your senior command NCO "off the record" with the details. A command NCO will talk to the CO and a good CO will remind the junior officers how to address subordinates in a professional manner.

In every service, there are documents and regulations that keep mutual respect in mind, as well as phrases and words that might easily pass as fraternization; I got into leadership positions early in my Naval career, but I never allowed my juniors to call me by my first name. It was sometimes uncomfortable as I rose up in the chain of command, as my senior enlisted tended to call me by my first name in private, never in public, because I was more their age and life experience. When I was the most senior enlisted on the command, I would allow the CO and XO to call be by my first name in private, and I would never reciprocate, unless they insisted, as long as it would pass scrutiny as not being construed as favoritism. I would advise a commander to eschew calling anyone by their first name in public, and would remind them of the rules on fraternization, as they were developed to promote command cohesiveness.

Who cares? This really sounds petty. You should feel lucky that the officer took the time to learn and remember your first name, Id consider it a compliment and only makes him seem more personalable. I find this far better than an officer thats disconnected

Politely and consistently ignore him. When he calls you on it, apologize and tell him of your confusion since you have gotten used to being respected enough by others to be addressed by your sir name especially since you don't know if there are any others with your first name which you only respond to when the women in your life use it. This worked for me

This is like an NCO refusing to call an Officer "Sir" and instead using his rank, or the abbreviation like L T. It goes both ways.
Now if a senior officer who has known the Sergeant a long time calls the NCO by his first name it is not a professional thing to do in a public setting. For a Junior Officer to do so publicly are really not that smart when the NCO objects.

I had a Lt that called me by my first name when i was his Plt Sgt but never in front of other soldiers if you dont like it tell them if they dont change then take it up the chain of command

I would mention it to another officer that you find it unprofessional. He may take it a lot better from a peer.

I serve for 39 years, during all this time there was only 3 way's to address and NCO "Sergeant" "1SG" and "SGM"

This response is purely opinion but ill share it none the less. An officer knows he outranks his NCO's. I have found that when an officer used my first name it was a sign of trust. In todays army theres a rift between the officers corp and NCO corp more often than not. I don't think every fine detail should constantly be scrutinized unless your loosing face with your troops.

As leaders, you will have to issue orders which may put personnel in difficult if not life threatening situations. If you personalize a subordination that removes the objective aspect of leadership. Professionalism must be maintained and I agree with LTC Curlee's statement whole heartedly.

Probable under the UCMJ. I would think.

While in uniform, In the Army or Marines and Air Force, the proper way to address anyone is by their rank and last name. Sgt Jones, Lt Smith. in the Navy (and Coast Guard) it would be Petty Officer Jones. Cdr Smith. Off duty, it all depends on the relationship of the people involved.

I always told my soldiers and officers that they could call me anything they wanted as long as they put SGT in front of it. It got the intended results.

I always said my first name is SGT. My last name is Fridley anything else is not Professional. Does this officer allow the NCOs to address him by his first name? I am guessing probably not.

Couldn't go wrong with using rank and last name to address I'd think. I think it's common to use Sergeant to all that it applies to at E-5 and above in Army. Not sure about the rest i.e. 1stSgt, SgtMaj as it applies to Army. Courtesy and respect apply also because they've earned it. The Bill, Bob, and Joe thing depends on unit & individuals I guess but I wouldn't think it would be common practice. The USMC Officers do that a lot but only senior addressing junior or equals in rank. Not a good idea for a Lt to address Bn Cmdr by first name unless he tells you to, which I've never seen. He's the boss though and whatever he wants, you give. Small and remote units might be less formal such as Spec Ops, small detachment like embassy duty, in academia etc.

Wow, I guess I must be one of the few that didn't think that an officer using my first name was degrading, fraternizing, or disrespectful when being spoken to. Guess I had too much of a mellowed out personality in that regard. Had a LTC that I was assigned as a driver for who asked my name and I gave the standard my name is Specialist to which he grinned and asked what my real name was. When it was just he and I, he was "Sir" and I was "John" in other company I was Specialist Wingfield.either way there was no disrespect up or down.

First off, tell your NCO,s to grow some , if if the officer calls them " John" then he also gets called John . as for you looking for "regs" you need to grow some also and quit feeling inferior.

There are specific times and circumstances that customs and courtesies can be relaxed, but only when both parties agree to that. ALWAYS use rank/name when subordinates or leaders and peers from other units are present. Professional military respect is our "payback" for the hard work and training we do, and it is expected of all of us; especially our leaders. Just do it!