The Foxes eased to victory against their struggling opponent, thanks to the Argentine's brace and a Wes Morgan header, to move further away from the relegation zone.
Ulloa opened the scoring after just 38 seconds at the King Power Stadium, and that set the tone for another fruitful afternoon for Nigel Pearson's side, which has now won five of its last six games to ensure its hopes of Premier League survival remain in the team's hands.
Captain Wes Morgan took advantage of more meek Newcastle defending to double Leicester's lead in the 17th minute, and Ulloa was on hand to convert a penalty shortly after the restart to seal a comprehensive win.
By contrast, Newcastle was woeful once again.
John Carver's team has lost eight matches in a row and sits just a point above upwardly mobile Leicester - with the visiting supporters making their feelings towards owner Mike Ashley known throughout.
Leicester made the perfect start when Ulloa nodded the side ahead in the first minute, the Argentinian brushing off the attentions of Moussa Sissoko to glance Marc Albrighton's corner beyond Tim Krul.
Newcastle responded well, with Ayoze Perez dragging a shot wide of the far post, but another excellent Albrighton set piece - coupled with shocking marking - proved the team's undoing 17 minutes in.
Albrighton swung in a dangerous free kick from the left and Morgan was on hand to toe poke past the helpless Krul from six yards after Ulloa just failed to make contact.
That goal sparked a prolonged spell of anti-Ashley chanting from the away end, and any hope the side may have had of an unlikely second-half comeback evaporated just three minutes after the interval.
Emmanuel Riviere inexplicably barged Marcin Wasilewski in the back in the area from a corner, and Ulloa stepped up to coolly fire his penalty high past Krul and end the game as a contest.
Leicester was brimming with confidence and Albrighton shot wide before Ulloa spurned a chance to get his hat trick when Krul made a brilliant point-blank stop from his header.
Newcastle's day went from bad to worse soon after when Williamson let his frustration get the better of him, needlessly scything Vardy down to earn a second booking.
Carver's men were going through the motions - typified by Janmaat's late dismissal - and could count themselves fortunate that Leicester was not more clinical in front of goal as Albrighton and Jeffrey Schlupp wreaked havoc down the flanks.
The score line at least remained relatively respectable, but the same cannot be said for Newcastle's attitude and the team is now undeniably involved in a relegation dogfight.