Green’s Dictionary of Slang

1. (US) a stupid, unreliable person.

1927		P. Kyne They Also Serve 14: Horses...who had made up their minds to go A.W.O.L. and quit being Joe McGees [HDAS].
1935		Charleston (W.VA) Daily Mail 27 June 8/8: ‘On the cob,’ ‘corny’ and ‘Joe McGee’, all of which pertain to obsolete methods of interpreting popular music.
1974		M. Cherry On High Steel 124: I don’t want [...] any Joe McGees they send out* [*A ‘Joe McGee’ is a dumb, goof-off, careless ironworker].

2. (US) among jazz musicians, banal, old-fashioned.

1928

W. Winchell Your Broadway & Mine 20 Nov. [synd. col.] [S]language [...] in use among musicians. [...] To refer to an instrumentalist as ‘corn-fed’ or ‘tinny’ is to term his jazz interpretations old style or ‘has been’ [...] ‘Mr Magee ’is also appropriate.

3. (also McGee, Mr McGee) a mean person, spec., a non-tipping hotel guest.

1935		Indiana Eve. Gazette 20 Mar. 9/2: In Manhattan hotels, any guest who doesn’t tip is known among the bellhops as ‘Mr. McGee.’.
1939		‘Hotel Sl.’ in AS XIV:3 Oct. 240/1: mcgee, joe mcgee Non-tipping guest.