A lot of thought went into that haircut, friend-o.

[The haircut] is wedgy, greasy, somehow old womany, and that, combined with Bardem’s machismo, makes it unsettling. The actor himself is supposed to have reacted, “Oh no, now I won’t get laid for the next two months,” when he saw it.

Now the man behind the cut has emerged. He is a Canadian hairdresser from New Brunswick called Paul LeBlanc who has previously styled hair on movies such as Star Wars and Casino, and who shared an Oscar with make-up artist Dick Smith for his work on Amadeus.

Le Blanc says that his inspiration was from the crusades, “when knights and Muslims were murdering each other, and this was a typical haircut. It was a dangerous time and we wanted to make Javier timeless and dangerous at first sight.”

https://www.theguardian.com/film/2008/feb/28/fashion.oscars2008