How does one become a Subject Matter Expert (SME)?

A Subject Matter Expert is an individual who not only knows THE BOOK (tm) chapter & verse but has real world experience on what ACTUALLY WORKS, and knows what short-cuts may be safely taken and under what circumstances.

When i was doing Expert Systems research that SMEs would give the book answer when asked THE QUESTIONS (tm). But if you asked them to DEMONSTRATE, the REAL SOLUTION (tm) would come out.

Good luck.

To be a subject matter expert I would have to say it isn't just about knowing the rules and regulations but having experience in it as well. Physical security is a perfect example because at one of the places I was stationed I worked with some people that did all kinds of security of information and one of our SME's has had years in the physical security field and doing inspections and knew the key regulations like the back of his hand because he has had to look in them and still continued to look in them for any changes. When they would do different exercises he would get called up to be part of the IG inspection team to make sure they were handling things properly.

Attend the Physical Security Course (There are 3 different types, you would want the longest one I believe) and then work as the Physical Security Officer.