The second season, which will air in the UK next year on BBC Four, kicked off on Sunday (July 27) on US cable and satellite channel AMC.
It reunited viewers with leading character Don Draper and his attempts to balance his complicated private life with the office politics of Madison Avenue ad agency Sterling Cooper, where he is partner and creative director.
Reviews in the American media have praised the show, which opens two years on from season one, with critics not shying away from the purplest of prose to describe the drama's return.
The New York Times said the new season "beguiles like a Christmas catalogue of all the forbidden vices, especially smoking, drinking and social inequity"; while TV Guide described it as "crisp as a martini, yet spicy as a Bloody Mary, the intoxicating 'Mad Men' goes down smooth and gives great afterglow, but can also leave you with a hangover of unease".
The San Francisco Chronicle said that the first two episodes "reaffirm ['Mad Men''s] place in the upper echelons of television drama"; while The Boston Globe said 'Mad Men' was "a tour de force of starched-white emptiness and emotional evasion".
The second series, according to Variety, is an improvement on the first: "['Mad Men'] is becoming richer as these plot strands grow... establishing an engrossing serialised life beyond the hip, reverberating cultural references that demonstrate the smoking-drinking-closeted sixties aren't necessarily good ol' days to be mourned."
As well as Draper, Elisabeth Moss returns in the second series, having moved on from her role as Draper's secretary Peggy Olsen, after breaking through the era's widespread misogyny, to land a role as a junior copywriter in the conclusion of the first series.
BBC Four won plaudits for picking up the first series, which was awarded the Golden Globe for best television drama series this year. The Daily Telegraph said the BBC pulled off "something of a coup" to secure 'Mad Men', which the Daily Mirror described as "cool and classy".
Sue Deeks, head of series BBC programme acquisition, acquired the series for BBC Four.
While UK viewers will have to wait until next year, they can at least enjoy the trailer now: