But England's dominance eventually shone through and tries from Maro Itoje, Howard Packman, Nick Tompkins and Joel Conlon secured the win while Billy Burns added 13 points with the boot.
After an early Burns penalty, England had their first try - lock Itoje pounced on a loose ball just past the Irish try-line for his third try in as many games.
Burns added the extras - and two more penalties - to make it 16-3 after 25 minutes, Ross Byrne with Ireland's penalty.
Byrne added two more kicks soon after which brought the visitors to within seven of England, which is how it stayed until the break.
The hosts started the second half as they did they first, and had their second try after 46 minutes.
Wing Packman - making his first start - was on the end of a smart pop pass from Nathan Earle and the Saints man showed good pace and footwork to dive over in front of his own fans.
After a spell of Irish pressure England had their third try through Tompkins. A quick burst from debutant Henry Taylor created space for Burns to grubber through and the Saracens centre touched down.
With England in the ascendency they continued to make their pressure tell, and after a spell camped in the Irish 22, flanker Conlon eventually touched down from the back of the scrum to make it 33-9.
Head Coach Nick Walshe said:
"Ireland are a good side and had a real go at us, but we held firm and managed to put a decent score on the board. The positive thing is that we still feel that there is more to come from the guys. We'll take a look back at this game now and identify what we need to work before we play Wales in Newcastle."
Captain Callum Braley added:
"We knew that Ireland would come out fighting and so it proved - they came at us from the first minute and I don't think we felt comfortable at any point. It's always pleasing to get the win and I'm delighted for the lads who all put in big shifts."
Points: Itoje 1T, Packman 1T, Tompkins 1T, Conlon 1T; Burns 3P, 2C
England Under 20 side against Ireland
15 Nathan Earle (Saracens)
14 Zach Kibirige (Newcastle Falcons)
13 Nick Tompkins (Saracens)
12 Harry Sloan (Harlequins)
11 Howard Packman (Northampton Saints)
10 Billy Burns (Gloucester Rugby)
9 Callum Braley (Bristol Rugby, captain)
1 Alex Lundberg (London Wasps)
2 Harry Thacker (Leicester Tigers)
3 Scott Wilson (Newcastle Falcons)
4 Maro Itoje (Saracens)
5 Charlie Ewels (Bath Rugby)
6 Ross Moriarty (Gloucester Rugby)
7 Joel Conlon (Exeter Chiefs)
8 James Chisholm (Harlequins)
16 Jack Walker (Leeds Carnegie) on for Harry Thacker 53 mins
17 Danny Hobbs-Awoyemi (Northampton Saints) on for Alex Lundberg 48 mins
18 Paul Hill (Leeds Carnegie) on for Maro Itoje 78 mins
19 Tom Ellis (Bath Rugby) on for Charlie Ewels 53 mins
20 Gus Jones (London Wasps) on for James Chisholm 59 mins
21 Henry Taylor (Loughborough University) on Callum Braley 58 mins
22 Sam Olver (Northampton Saints) on for Billy Burns 60 mins
23 Henry Purdy (Leicester Tigers) on for Nathan Earle 46 mins
Content courtesy of RFU