Leaving 'Mad Men' aside, there is a look that often crops up in movies, on TV, sometimes in advertising, often in black and white studies sold on Ebay.  I still have a few of those, tucked away in cardboard boxes. 
A hat of some description is almost always involved.  This hat will most often have a band.  A dark suit comes to mind.  Probably a white or blue shirt and a tie in some restrained pattern else solid.  Shoes will be hefty.  No loafers.  There will often be a raincoat, either worn or carried across one arm. 
The wearer may have worn 'Ivy' clothing as a college kid but has moved on into the big bad world of work.
It's close - possibly - to the Brooks look of 'Don't Stand Me Down'.  But maybe not that close.
It looks utterly, utterly Big City American but variations will probably be found everywhere.
He may wear a bowling shirt and chinos when off guard/duty.  Not sure about the footwear. 
Anyone identify this look?  Just 'man in grey flannel suit'?