Oram's 101, his fifth century in his 28th test, guided New Zealand from strife to safety at 269 for six when the gathering gloom forced an early end to a weather-marred test.
It hauled up a New Zealand second innings which was teetering at 120 for four, an overall lead of just 78, and with key man Brendon McCullum in hospital getting x-rays on his badly bruised left forearm which was struck by a Stuart Broad delivery.
Thankfully for the tourists, McCullum was cleared of broken bones as Oram and debutant Daniel Flynn added a crucial 132 for the fifth wicket to ensure the team head to Manchester for Friday's second test in a buoyant mood.
"It's the proudest moment of my career so far, it's surpassed anything I've ever done before," Oram said.
"I rode my luck a bit, and to be honest I couldn't give a toss how it really looked because at the end of a day it's a hundred and it's on the honours board now."
Oram batted 131 minutes, faced 121 balls and hit 15 fours and two sixes; one a slog-sweep off Monty Panesar and the other a towering straight hit off part-timer Kevin Pietersen into the second tier of the Members' Stand.
He was eventually bowled by his nemesis Ryan Sidebottom, soon after he'd hit him for three consecutive boundaries with the new ball to bring up his century.
Oram arrived at Lord's under a cloud, with just 55 runs from six test innings since his 117 against Bangladesh in January.
His previous century was back in April 2006 against South Africa at Centurion.
He batted 146 minutes for 28 in the first innings and decided to revive his old attacking approach with New Zealand badly in need of a hero.
"This wasn't technically my best work and I'm still having problems at some stages of the innings, especially against one bowler in particular (Sidebottom).
"It's a hundred and you've got to battle through tough times and I've been pretty lean for runs lately.
"That's why they call it test cricket. It's a good challenge and I'm just so proud to come out the other side in a positive way.
"I don't think there was a better way for me to come in, with a bit of pressure on us. It was a chance to get in at a time the team really needed me and I think I enjoy those moments."
Fellow left-hander Flynn, 23, deserved almost as much kudos for his unbeaten innings of 29 where he batted 163 minutes while Oram swished away.
He showed sound technique, suggesting a move up the order wouldn't be beyond him as he rarely looked troubled by the England attack.
"He's extremely composed and that's the big thing that struck me out there," Oram said.
With Oram's dismissal to a standing ovation, McCullum bravely returned swinging and added another 13 runs before being caught behind for 24.
Opener Jamie How provided the platform with a solid 68 including nine boundaries.
Aaron Redmond, James Marshall and Ross Taylor all failed to top 20 and when How departed caught at third slip off James Anderson there were some jitters at 115 for four.
Captain Daniel Vettori was named man of the match for his five for 69 and said his young side would take out added confidence.
"Guys stood up all through the game, particularly the senior players, along with performances by Jamie How who played really well and Daniel Flynn who had a composed, mature innings for such a young guy in his first test," he said.
