The former Oasis frontman picked up the accolade six years after his brother Noel was given the same honour.
He said he should have been recognised sooner.
He told Sky News: "If you're going to give one brother one, you should give the other one, so I was a bit put out with that, you know what I mean?" he explained on the red carpet for the event in London.
"But then again, best things come to those who wait I guess."
I asked Liam if his brother had been in touch to congratulate him.
"Nah nah no, I don't speak to that clown," Gallagher said.
"He's too busy writing cosmic pop and sharpening his scissors, and trying to convince the Americans that it's the way forward."
The scissor reference follows Noel's recent use of a scissor player on stage at his High Flying Birds concerts.
NME's Editor in chief Mike Williams presented the award to the Wall Of Glass singer, saying: "This is a man who understands exactly what it means to be a rock'n'roll star."
But Gallagher said he doesn't want to be one of a dying breed.
"I hope not, I'm just one of many. But there's not many here tonight I don't think."
He explained why he thinks there's not as many stars subscribing to the rockstar status that he holds.
"You're not allowed to say anything anymore are you? If you say anything you get a slapped wrist and that y'know what I mean?"
"Apparently guitar music ain't that trendy anymore so they've all jumped ship, and they've got keyboards round them, it's their fault for jumping ship because it's always been cool and I think it'll come back round.
"So the ones who'll come back and put their guitars back on - shame on them y'know what I mean - whoever they are."
Other winners at last night's NME Awards included Kasabian for best live act, J Hus who was awarded best album and Garbage frontwoman Shirley Manson who was given the Icon prize.
List of Winners:
Best British Solo Artist Loyle Carner
Best British Band Alt-J
Best Album J Hus - Common Sense
Best Festival Glastonbury
Best Festival Headliner Muse
Best Track Charli XCX - Boys
Best Live Artist Kasabian
Best International Band HAIM
Best International Solo Artist Lorde
Best New Artist Stefflon Don
Best Mixtape Avelino - No B*******
Best Collaboration Craig David and Bastille - I Know You
Best Film Baby Driver
NME Under The Radar Pale Waves
Best Music Video The Big Moon - Sucker
Innovation Award Boy Better Know
NME Icon Shirley Manson of Garbage
Godlike Genuis Liam Gallagher
