I’ve seen that in some engineering companies there are some contract experts are working whose majors and academic backgrounds are irrelevant to this position. For instance, one is a chemical graduate but is working as contract and legal affairs expert. Is it merely because this person has been involved in this type of job - not his own field - for a long time, and now he has obtained enough experience to handle this position? Or are there some other reasons?
Usually the role of a contract administrator is not to deal with the legal aspects of contracting – he hires lawyers to do that for him – but to address the substance of the contract. His area of expertise is the project or service to which the contract relates. So in, say, a contract for a complex engineering or construction project, he understands what the project entails, and how that needs to be reflected in the contract. Exactly what services need to be provided if this project is to succeed, and what materials will be required, and what regulatory and other approvals will be required, and who should attend to all these things, and who is responsible for making sure that they do, and what timeframe and sequence is to be followed, and what the implications for the project will be if it isn’t followed, and how that might be addressed if it happens, and who will be responsible for addressing it . . . You get the picture.
And, having ensured that the contract negotiations result in a contract which addresses all these questions satisfactorily, the contract administrator usually has a continuing role to play in the implementation of the contract, in making sure that it is adhered to, in spotting if circumstances make contract variations necessary and, if so, taking steps to negotiate and agree them, etc, etc.
He’s not a lawyer and he doesn’t have to be and doesn’t pretend to be. There will be lawyers involved as well, and he will work with them. He usually take the lead role in instructing them, in fact.
I’m a music grad who works in contract admin and regulatory affairs for an insurance company.
Started at the co. as an entry level claims examiner and worked my way up. For this gig in particular, one needs to know insurance benefit design and have direct experience with our products.
No way for someone outside the co. to get this gig. Has to be internal with specific experience. Half my coworkers don’t even have college degrees.
Encyclopedic ! Thanks.
How good that despite being outta your field, still you have a gig ! 
And, are they getting as much salary as a person holding the relevant degree gets?
Yes - as far as I’m aware. The salary range is the same regardless of past experience/education.
Though I don’t even know what a “relevant” degree would be besides something rather generic like business admin or something.
They generally don’t get as much as the lawyers, if that’s what you’re asking.
Some of us do but you are right as a general rule a lawyer gets more as they are bought by the hour…