Pardew swapped St James' Park for a return to Palace in early January after spending five mixed years in charge on Tyneside.
However, in a largely lacklustre affair, Pardew initially looked set to preside over a seventh consecutive home defeat for Palace against Newcastle following Papiss Cisse's first-half opener.
Despite being on the back foot for much of a dour first half, Cisse gave Newcastle a half-time lead after heading home Daryl Janmaat's cross from the right three minutes before the interval.
However, the hosts persevered after the break and, while they struggled to muster too many chances of note, Campbell made the most of one 19 minutes from time as Newcastle failed to hold onto a one-goal lead for the second time in four days.
Palace made the more purposeful start - the recalled Yaya Sanogo laying on an early chance for Wilfried Zaha down the left that forced Tim Krul into a routine stop.
Despite their greater possession, it proved the home side's only clear-cut chance of a low-key opening 20 minutes before Palace's frustrating first half was made worse by the injury-enforced exit of Sanogo.
A clever header from his replacement, Campbell, 10 minutes before the break looked to have broken the deadlock – only to be denied by the offside flag - before the visitors took the lead with their first attempt on target.
Janmaat burst past Zaha and crossed for Cisse - one of two Newcastle changes from Sunday's 1-1 draw with Stoke City - to head home unmarked inside the penalty area.
A scrappy start to the second half was punctuated by fouls from Janmaat on Zaha and James McArthur on Remy Cabella as sloppy defending from both sides offered glimpses of opportunities.
Newcastle eventually scrambled clear Zaha's delivery - following Jason Puncheon's knockdown - before Cabella's teasing cross was shepherded out of harm's way by Brede Hangeland.
Pardew brought Dwight Gayle and Yannick Bolasie on after the hour mark to further bolster Palace hopes and it was a dangerous cross from the latter that allowed Campbell to sweep home the equaliser.
Cisse went close again soon after with his last taste of action before being replaced by Mehdi Abeid, while Hangeland threatened twice from Palace corners late on.
However, in a far from classic encounter, neither side truly did enough to warrant maximum points as Palace edged a point closer to Premier League safety in 13th.
For Newcastle, the draw represents a missed opportunity to move into the top half at the expense of Stoke, who lost 4-1 to Manchester City.
