Holloway, who quit Blackpool to take over at Selhurst Park at the weekend, took charge for the first time on Tuesday evening as a hat-trick from Glenn Murray, in between Yannick Bolasie's opener and Andre Moritz's late strike, stretched Palace's unbeaten run to 12 matches.
Murray scored twice from the spot, and also missed a third penalty, as the Eagles ran riot to condemn new Ipswich boss Mick McCarthy to a first defeat in his second match at the helm.
Holloway did not have to wait long to see his new side get off the mark as Bolasie chased Owen Garvan's ball over the top in the 24th minute.
As Ipswich waited for an offside decision against Murray, who was trotting back from goal, Bolasie nipped clear and neatly chipped in his first for the club.
Murray thought he had doubled the lead 10 minutes later but this time the offside flag did go up and the effort was ruled out.
Ipswich's best chance of the first half also came via a Palace player when defender Jonathan Parr attempted to divert a cross over his own goal, forcing Julian Speroni to tip the ball to safety.
Moments later Wilfried Zaha, the teenage winger Palace say they will not sell for less than £20million, jinked his way into the area but Town keeper Stephen Henderson stuck a leg out to save.
Five minutes after the interval Palace doubled their advantage. Again Zaha tip-toed his way into the box and this time he was brought down by Luke Chambers, allowing Murray to step up and score his first from the spot.
And five minutes later Aaron Cresswell was penalised for a foul on Murray and the striker again made no mistake.
Murray's first chance for a hat-trick arrived on the hour when Chambers fouled Garvan, but this time he blasted the penalty straight at Henderson.
However, barely a minute later Murray did complete his treble, and took his total for the season to 13, when he slid in to convert Joel Ward's cross.
And substitute Moritz tucked in Parr's cross to round off the win in stoppage time and leave Holloway celebrating a stunning start to life in south London.