The veteran paceman was supreme, taking the 20th five-wicket haul of his career as Ireland were dismissed for 172.
England's openers Duckett and Crawley then tucked into an appetising Ireland attack after tea as the hosts reached 152-1 in only 25 overs to seize control of the four-day test.
Left-hander Duckett was particularly impressive as he reached his sixth test half-century from 53 balls, ending a one-sided day on 60 not out.
Crawley, yet to convince as England's first-choice opener despite 32 previous tests, reached his 50 off only 39 balls as Ireland's attack wilted.
Crawley fell for 56 but Ollie Pope continued the punishment with 29 from 35 balls before stumps.
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The one-off test is very much an aperitif for the Ashes starting in a fortnight and there was a buzz of anticipation around the ground as captain Ben Stokes won the toss and invited Ireland to bat on a greenish wicket under an overcast sky.
Ireland, still looking for their first win as a test-playing nation having lost the previous six, slumped to 19-3 as Broad, appearing in his 162nd test match, wrought havoc with three wickets in an eight-ball spell.
First, he trapped Peter Moor (10) lbw with a full and straight delivery and on the first ball of his next over Ireland captain Andy Balbirnie dangled his bat outside off stump and edged to Crawley who took a fine slip catch.
Two balls later Harry Tector flicked a rising Broad ball off his body straight into the hands of Matthew Potts at leg slip.
Broad's next delivery rapped Paul Stirling's pads and he was given out but reprieved after a review.
Spirited Fightback
Ireland were bowled out for 38 in their previous innings at Lord's four years ago when they were chasing a modest target of 182 for what would have been a historic victory.
There was no repeat of that shambolic collapse as Stirling launched a spirited fightback alongside opener James McCollum.
Stirling struck England's debutant seamer Josh Tongue for successive boundaries in the 16th over and also went after spinner Jack Leach but was out for 30 off 35 balls when he gloved an attempted sweep off Leach behind to Jonny Bairstow.
Having reached 78-4 at lunch and with the sun bursting through, Ireland might have hoped to reach 200 at least.
McCollum moved to 36 after lunch before edging Broad to Joe Root at first slip and then Lorcan Tucker (18) fell lbw to Leach when he missed an attempted sweep.
Curtis Campher and Andy McBrine shared a 38-run stand before McBrine attempted to drive Potts through extra cover but nicked behind to Bairstow.
Broad completed his third 'five-for' at Lord's and first at the home of cricket for 10 years by clean bowling Mark Adair (14) before Campher (33) was bowled having a swing at Leach.
Potts finished it off by having Fionn Hand caught behind.
With sumptuous batting conditions, the only question then was whether England would be ahead by the close.
They just failed but should pile up the runs on Friday.
