Mac is a smidgen above average height, with a medium build and about 20 extra pounds around the midsection. He has thick salt and pepper hair gone full gray at the temples and he stays clean shaven. He wears his hair off the ears and collar and combed back with enough product in it to keep it in place. A ten dollar haircut not quite Navy short, but close to it.
His face is square with heavy features, deep creases and a ruddy complexion. A very Irish face most would say, one that would look right at home on a cop in some 1950's movie. His eyes are hazel and are deep set and often have bags under them. In unguarded moments they look as if they have seen too many things no man should see, but usually they are bright and sharp with humor. A smile comes easily to his lips and there is a spring to his step that belies the otherwise weary look.
Mac smells faintly of hair gel and slightly more strongly of dime store cologne or aftershave.
Mac wears suits. It is rare to see him in any other attire. His are not the suits of well off businessmen or lawyers, his are the suits working men wore in the 50's. He looks far more casual than professional, and one could describe his appearance as frumpy. On warm days he favors a straw colored rumpled linen suit with a straw boaters hat, and on cooler days he is likely to be wearing his brown corduroy suit and plaid fedora. In either case his shirt is an off the rack light colored dress shirt and his tie and belt wide black ones. His tie tack and cufflinks are plain silver rectangles. His footwear is comfortable well worn boater shoes that color match the suit, more or less, with argyle socks.

Mac is a bacon and eggs, steak and potatoes sort of guy. A relic of a bygone era. He's stoic in his outlook, fatalistic some would say, although it's an upbeat fatalism. He has a sense of humor, but it's sometimes dark despite an often easy going demeanor. Mac is also very capable of violence, and although he seems non threatening he can turn violent in an instant. He has a distrust of authority and disregard for laws despite having a fairly strict morality.

Mac is a Chicago native, his father was a well liked cop, although also a corrupt one. Mac himself is a gunsmith dealing in black market guns for the mob.