Back in the day

[fredpuli47]

'Back in the day' seems to be an American expression. Is it? Or is it an an English expression which became obsolete in Britain? When was it first recorded ?

[Clanad]

It appears that you're correct in that it's origin was here in the U.S., however, more specifically, it doesn't appear to date much earlier than the mid-1990's... This quote is a definitive as I can find:

"Dr. Geneva Smitherman, author of “Black Talk,” is distinguished professor at Michigan State University and director of its African-American Language and Literacy program. “When used by middle-aged and older members of the black speech community,” she informs me, “ ‘back in the day’ refers to the 1960s and often reflects a kind of nostalgic longing for a historical moment when there was a very strong black unity. . . . When used by members of the Hip Hop Generation, it generally refers to the beginning phase of Hip Hop Music and Culture, in the ’70s in the South Bronx. Hip Hop music of this period was more rooted in Black Cultural Consciousness, in contrast to the 1990s advent of ‘gangsta rap,’ with its emphasis on violence, misogyny and bling-bling.”

The Hip Hop Archive at Stanford University is directed by Prof. Marcyliena Morgan. “When ‘back in the day’ is used by youth to refer to Hiphop eras, there is no problem,” she said. “However, if an 18-year-old used it in reference to when he or she was 15, it is often considered preposterous.” “Ahmad (a rap artist ca.1994) in his song ‘Back in the Day’ reminisces about childhood, but also includes references to artists and clothes, etc., that defined the Hiphop era.”
Obviously a 'corruption' of "Back in my day"...

[fredpuli47]

Clanad, that explains something. An advert running here has an old hippy reminiscing. There's a flashback to a hippy festival and he comments 'Back in the day, everything was free, now you need a mortgage to get a ticket...' So the advertiser has the phrase exactly in period .

However, there's a fashion, among some people here in Britain, for saying 'Back in the day' when they mean 'back then' , 'in those days' or even 'a long time ago, but in my lifetime'..

[Quizmonster]

The earliest recorded use of the phrase, according to the OED, was in a Beastie Boys song called 'Girls', recorded in 1986. Brooklyn lads, so yes, American in origin.

[Clanad]

Podunk...

[junk19082]

I heard this used as early as the early '80's by a resident of Trenton, NJ (to place the location of its apparent popular use). My recollection through the years is that it was used primarily by and among persons who were (let's say) not particularly well-educated. It has certainly come into widespread use since then, particularly in the last 10 or so years, and is even used now by persons other than those of the social stratum where it seems to have originated. It is an irritating and mildly stupid phrase dripping with ersatz nostalgia and is a lazy and careless way of referring to some time in the living past whose particular date or era cannot readily be recalled with precision.