Who knew?

The surgeon general wears a uniform because the organization of which she is the chief, the U.S. Public Health Service, is a uniformed service. So are mail carriers, you may say, but the postmaster general doesn't get to dress like Horatio Hornblower. The difference is that the PHS began as the Marine Hospital Service, which was organized along military lines in 1870 to minister to merchant sailors. The members were (and still are) given military-style commissions and naval-style ranks, the idea being that they were a mobile force ready to be thrown into the fray wherever germs raised their ugly little heads. One supposes the fact that MHS doctors often served alongside regular military personnel (e.g., in military camps during wars) and sometimes had to order them around also argued for ranks and uniforms. The Marine Hospital Service was reorganized as the Public Health Service in 1912 and transferred to what is now the Department of Health and Human Services, but the military trappings remain.

(The Straight Dope)

And what about the attorney general? "General" is an adjective in that title, explained William Safire in a 2003 column:

Is it right and proper to call an attorney general "General"?

The answer is no. Any attorney general, national or state, who demands to be called "General" is guilty of nominally impersonating an officer, an offense almost as horrendous as aggravated mopery.

Sorry, Alberto. Wrong again.