Leeds, fielding new signings Andy Lonergan and Michael Brown, burst into a fifth-minute lead when Patrick Kisnorbo was in the right place to take advantage of a piece of poor handling from Newcastle's Fraser Forster.
The Whites' early dominance continued and they could have doubled their advantage when Max Gradel headed home, only for him to be denied by the offside flag.
Newcastle found their stride and levelled 10 minutes before the break when Steven Taylor nodded home a corner at the far post, amid claims of a foul on Brown.
It had been an encouraging performance by Simon Grayson's men and the Elland Road crowd had even more reason to cheer midway through the second period when substitute Lloyd Sam restored the home advantage by firing in from a tight angle.
It was a lacklustre performance from the Premier League side throughout, but they levelled for the second time in the game when Haris Vuckic powered past Lonergan with 14 minutes to go.
But Leeds were not to be denied a deserved victory as Billy Paynter struck home his first goal of the pre-season campaign to leave Newcastle boss Alan Pardew to reflect on a sub-standard display.