I heard this term dropped a bunch on DEADWOOD...

A massive Ian Hunter fan.

Nah, it goes far deeper than that...into catecombs and secret ceremonies (sort of like Masons and Rosicrucians and Opus Dei.) Ian Hunter and band were already hoopleheads themslves paying tribute to their spiritual leader, the Mr. Natural of his day, Major Hoople:

Urban Dictionary has a few entries:

http://www.urbandictionary.com/define.php?term=hoople-head

http://www.urbandictionary.com/define.php?term=hooplehead

http://www.urbandictionary.com/define.php?term=hoople+head

http://www.urbandictionary.com/define.php?term=hoople

This is the one I liked the most:


a member of the ignorant masses; an uneducated commoner; an idiot. word popularized by HBO's Deadwood

Try not to use big words-- it confuses the hoopleheads.

I was somewhat joking when I tossed in Major Hoople, but this online hooplehead investigator is convinced that we need look no further for the Deadwood term's origins:

http://www.worldwidewords.org/qa/qa-hoo3.htm

The comic strip character made his entrance onto the stage of "Our Boarding House" only in 1922, long after Deadwood takes place, but long before it was created. The author supposes hoople and hooplehead are backdated anachronisms that sound like they belong in historical context, but didn't. If all this is so (???), it seems of a piece with the 'true to life' seeming yet historically unlikely salty vocabulary of the Deadwood folks. I'd suggest 'hoople' got conflated with 'hophead' to create a expletive deleted-head/same expletive-for-brains type combo, a 'you sorry idiot!' term of dingbat endearment.

For the record, Mott the Hoople took its name from a sixties novel which may have borrowed its name in turn from the boarding house strip: both featured small account grifter hooples.

There was a Canadian band that took its name from the strip directly: Major Hoople's Boarding House.

Sounds like a real Herkimer!