Tigers manager Nick Barmby is hoping that the 20-year-old will have a similar impact at the KC Stadium to that of Frazier Campbell in 2008.
"It's a very similar situation to when we brought Fraizer Campbell here," Barmby told the Hull Daily Mail. "Fraizer came in as an unknown quantity but players can make a name for themselves here and use the loan as a platform.
"We're delighted to get Josh in. I first saw him play two or three years ago and I've kept tabs on him ever since.
"He's an exciting player. Josh will fit into the way we play and it's a great chance for him."
King has made one appearance for the Manchester United senior team.