The 29-year-old USA international becomes the club's second signing of the transfer window after the arrival of Roque Santa Cruz from Manchester City.
'He's a fantastic signing for us,' manager Steve Kean told the club's official website.
Rover and done: Blackburn have completed a loan deal for Schalke midfielder Jermaine Jones
'Anybody who knows him as a player, he's a natural ball winner, he's a very good passer as well.
'He's got a fantastic engine, he can go box-to-box, he's a genuine all round midfielder player.'
Jones, who was born in Frankfurt, made three friendly appearances forGermany before being cleared by FIFA to switch his allegiance to the United States in 2009.
New blood: Jones joins Roque Santa Cruz as Blackburn's second capture of the January window
Jones is eligible to play for the USA because his father is American. He made his debut for the country in October 2010.
The midfielder has been at Schalke since 2007, but has fallen out of favour with coach Felix Magath.
Rovers will now await international clearance.
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Explore more:People: Roque Santa Cruz, Jermaine Jones, Felix Magath Places: Germany