Your variant works, but it sounds a bit literary.
The neutral pronoun is как... так и.... So the neutral register is 'все мужчины, как старые, так и молодые...' (or even simpler, double и...и - и старые, и молодые) But maybe your variant could work better if one needs to sound ironic (more sophisticated, etc.).
И стар, и млад... needs clarifying. This is an idiom (so it's more of less fixed, with a fixed meaning, so the deviations suggested before like "ни стар, ни млад" probably exist, but rare and not typical). But the fixed meaning is 'ALL people, regardless of sex, including children, everyone'... In your case you need to say it's 'men only', so I would be cautious to use "и стар, и млад" - it may be used probably to refer to men in some contexts if you specify it's men only, but logically it's not 100% impeccable, for strictly speaking it includes women and children, hence may sound ironical or funny if the phrasing is not exact. Besides, и стар, и млад (having archaic connotation, младой - is archaic form) in itself may sound ironic.