publicity expert; PR person; hype man
Often carries a slightly informal or colloquial tone, implying someone who is good at drumming up attention, sometimes with a nuance of exaggeration or showmanship.
As the company's publicity man, he promoted the new product with a lot of fanfare.
That politician hired a skilled PR person to improve his image.
Compound of 宣伝 (publicity, advertising) and 屋 (shop, or suffix for a person with a certain trait or occupation). The suffix 屋 often adds a colloquial or slightly derogatory nuance.