Midfielder Joey Barton and striker Andy Carroll scored in the final 10 minutes to give Pardew, who was appointed on Thursday as the replacement for the fired Chris Hughton, the perfect start to life at the northeast club.
Newcastle captain Kevin Nolan, a Liverpudlian like Barton, put the home side ahead in the 15th minute but Netherlands forward Dirk Kuyt leveled in the 49th with a deflected shot.
The win lifted Newcastle into eighth place on 22 points, above 18-time champion Liverpool on goal difference.
The popular Hughton was fired on Monday despite leading the team out of the second-tier League Championship and into a mid-table position in the Premier League.
Former West Ham, Charlton and Southampton manager Pardew was seen by some as a controversial replacement but he couldn't have dreamed of a better start to his tenure at St. James' Park.
Barton's free kick in the 15th minute was headed down by Carroll for Nolan _ a lifelong Liverpool fan _ to sweep home from close range and put Newcastle ahead.
Carroll's low shot was then saved by goalkeeper Jose Reina before Liverpool got back into the game and almost drew level.
Raul Meireles' low shot was deflected goalward off the legs of Reds striker David Ngog, only for Newcastle left back Jose Enrique to clear off the line.
Liverpool defender Sotioris Kyrgiakos flashed a header across the face of goal just before the break but within four minutes of the second half, his team had equalized.
Newcastle defender Sol Campbell failed to deal adequately with a long ball and Kuyt took advantage, running through into the area and firing a shot that deflected off Steven Taylor and spun past goalkeeper Tim Krul into the bottom corner.
Minutes later, Krul produced a good save to deny Spain striker Fernando Torres, back in the Liverpool team after missing the 3-0 home win over Aston Villa to be present at the birth of his second child.
Newcastle looked more dangerous going forward, however, with Carroll heading over in the 56th and substitute Nile Ranger shrugging off a challenge by Martin Skrtel but shooting narrowly wide in the 64th.
The hosts were not to be undone as Skrtel failed to deal with another flick-on by Carroll and Barton nipped in to toe-poke a finish past Reina.
The irrepressible Carroll then wrapped up the victory in the first of four minutes of injury time by smashing a low shot past Reina from 25 yards, with the Liverpool defense unforgivably backing off the England striker.