The Sunderland-born midfielder has been handed the Bairns’ number 10 shirt and moves after 13 games this term with the Staggies, including a start at the Falkirk Stadium in November.
His previous club before moving north, was Chesterfield.
McKinnon has now signed eight players in this transfer window and 11 in total since taking over from Paul Hartley on the last day of August.
MATCH PREVIEW: Partick Thistle v Falkirk
JANUARY TRANSFER TRACKER
IN: Ian McShane (St Mirren), Paul Dixon (Grimsby), Abdul Osman (PAS Lamia), Ross MacLean (Motherwell), Mark Waddington (Stoke), Shayne Lavery (Everton, loan), Ciaran McKenna (Duke University), Davis Keillor-Dunn (Ross County).